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TRANSCRIPT
Time Variation of Cosmic Ray Meson Intensity
FOR THE Ph. D. DEGREE IN PHYSICS OF THE
ALIGARH MUSLIM UNIVERSITY A L I O A R H
SUBMITTED BY R. S. YADAV, M. Sc. (Allahabad)
1965
T634
T H 1 3 I S
Oa
»«TIM1 V.4RlAfI01 OF C03MIG RAY MESON INfESRSIlT"
f o r t h e Ph.D. Degree i n P h y s i c s
of t h e
A l iga rh Muslim U n i v e r s i t y
A l i g a r h .
i I i
S a b a i t t e d by j
E . S . lADAV, M.Sc. (Al lahabad)
1965.
@m
CERTIFIED TEkT THE WORK PRESSI^Si) IN
THIS THJSLlu IS THE ORIGINAL' WOBK CARRIED OUT
B1 ME,
(RAJilNDEA blNQH YADAT) LECTtJESR
DEPARTMENT OP PICTSiC 5 A.M.U. ALIGARH.
Ill
AGKHOLEPgEMEHT
%lille s a l ^ i t t i j a g t h i s t h e s i s the au thor
wishes t o e x p r e s s h i s i n d e h t e d n e a s and g r a t i t u d e
to P r o f e s s o r fiais Ahmed, f o r h i s keen i n t e r e s t
and guidance i n t h e work, f h e au thor i s t h a n k f u l
to Br, P . S . G i l l , D i r e c t o r Gulmarg fie search Obse r -
v a t o r y , f o r p r o v i d i n g t h e f a c i l i t y t o work i n -ttie
O b s e r v a t o r y .
f h e au thor i s a l so t h a n k f u l to h i s c o l l e a g u e s
Dr. R.H.Mathur, Messrs Lekhv i r Sad, Gh. S a s t r y
f o r t h e i r h e l p i n c o l l e c t i n g d a t a a t Gulmarg and
a l s o t o Mr. A j i t S i n ^ , t h e g l a s s - b l o w e r , and Mr.
m^iaa ta l l&h t h e Dept. of p h y s i c s , A.M.U. A l i g a r h ,
f o r h i s h e l p i n c o n s t r u c t i n g t h e G-M c o u n t e r s .
f h e a u t h o r wishes t o thank p r o f . B.C, l o s e , N a t i o n a l
f lesearch Sbunc i l of Canada, f o r s u p p l y i n g d a t a f o r
Ot tawa, C h u r c h i l l , Sulphur Mountain and B e s o l u t e . The
a u t h o r i s g r a t e f u l to P r o f . B a r t e l s f o r supp ly ing
t h e magne t ic d a t a .
Hhe au thor a c k ^ w l e d g e s with thanks the f i n a n c i a l
s i p p o r t i n t h e form of a s c h o l a r a h i p g iven by the M i n i s t r y of S c i e n t i f i c Research and C u l t u r a l A f f a i r s ,
Govt, of I n d i a , i ^ i c h made i t p o s s i b l e f o r him t o
c a r r y o u t t h i s work. Rhwdh^ (B.S.^IADAV.)
JV
COHTiafTS
GHftl^SR I
1 . IRTRODTKTION 1
1 . 1 Dai ly V a r i a t i o n 2
1 . 2 So la r f l a r e e f f e c t on cosmic r ay i n t e n s i t y . . 6
1 . 3 Magnetic storms a s s o c i a t e d viith s o l a r f l a r e s . 8
1 . 4 Schene of t h e t h e s i s . . , . 9
1 . 5 Important r e s u l t s 11
CHAPTER I I
2 . SXPBRIMiSNTAL ARRAKGEME13T 16
2 . 1 G.M. Counters 16
2 .2 C o n s t m s t i o n of t h e t e l e s c o p e . . . . . . . . . . . . . 17
2 . 3 Arrangement f o r narrow ang le t e l e s c o p e s . . . 19
2 . 4 E l e c t r o n i c c i r c u i t s 19
2 . 5 Photographic arrangement 21
CHAPTER I I I
3 . DIURNAL VA-RIAIIGK OF COa^IC-RAY MESOH INTENSITy.23
3 . 0 1 C o r r e c t i o n f o r me teo ro log i ca l f a c t o r s . . . . . 25
3 .02 Harmonic a n a l y s i s 26
3 . 0 3 Study ^rlth c u b i c a l t e l e s c o p e a t Gulmarg . • 2 6
3 . 0 4 Study w i th t e l e s c o p e s of d i f f e r e n t a p e r t u r e s a t <lulimrg 28
3 .05 Day t o day changes i n the d i u r n a l v a r i a t i o n of cosmic- ray meson i n t e n s i t y . . 31
3 . 0 6 Dependence, of t h e d i u r n a l ampl i tude and phase on magnetic c h a r a c t e r f i g u r e C p . . . . . 35
V
3 . 0 7 1&© i<ro3?M«4?ide c o n g e s I n cosmic-^my mason i t t t e i i s i t y aiid t h s l v c o i r e l a t i o n -a l th s o l a r and g e o m g n e t i e a e t i v i t y « « , 3 9
3 . 0 8 a a p l i t u d o tto© plmss of a i u m a l
3*09 S3Q©r^ cteoeMQnee of th© d i t t i m l m ^ i a t l o n • 46
3 . 1 0 Sf>sil-41iimal i r s a l a t l o a 47
3 . 1 1 fhB i ^ l a t i o o s h i p t m ^ m s e s i - a i u f i m l • T a r ^ t i o a geomsgfiatie d i s t u r b a n c e s 51
3»12 Month t o mmtii cteaages I n ttes ampl i tude ai:ia i ^ s e of til© s ^ s i - d i i i r n a l aci^mxBat and t h e i r r e l a t i e j i ^ t h Cp v a l m s and
3«13 OrigSji of s emi^d iu raa l v a r i a t i o n 56
3*14 Biscmssimi 58
3 , 1 5 ^ p l a m t i o a of d i a n s a l ^ a n a t i o a s 61
CMmm 17
4» MTifuBB km mmmm:E O F m DIHRSAI* A® 0P COafSJ-aAT IHfBNSIfJT m
4*1 l a t i t a d o depoisdence o f t h e ampl i tado of t h e di t i iaml and s o s t - d l u i r a a l i r a r i a t iGa 7 3
La t i t t i d s dep^tidenea o f t h e p h a ^ of t h e d i i m j a l and s e s d - d i u r i m l -mr ia t icaa 7 6
4 * 3 A l t i t u d e depeMence of t h e phase 79
4*4 Bisc t i s s ion 82
C H i p m t
B* m m t OP fHS cMniit ? A B i m o H OF COSMIC-KAI i m m s i T t OH MAsimcAiKr ©XOTRBSD AHD q m m DAYS. ^ OIFFUaffl M f l f O I B S IH BOfH fHE H M I ^ E S ^ S 87
S«1 B i a i m l i r a r i a t i m m m g i a e t i c a l l y d i s t u r h e d aisd g t t i e t days 88
S . 2 f h e i^ isss of t h e d i rnmal "Variat ion on d i s t e i r l ) ^ sad < j i ie t d a ^ 95
Vi
6 , 3 Se f f l i - d iu iml coi^EKHa^it on and i fo t e t days «•»«»••
S»4 Al t i t ua© aspeM^ne© of plias© on d i s t u r l ^ a and q u i e t days 97
s t u d y of tbs jsatm-e of d a i l y i m r i a t i o i i of cosmic r ay i n t e n s i t y a t d l f f e i ^ n t l a t i t t s d e a I n fcotti t h e h e a i s p h e r e s * . • • » • « . « * » 9 8
S . 6 B l se t i s s ion and i a t e a ^ r e t a t l o n of
ett^PfBB ¥ I
6 . t m t m m m c E m mMM. FL&sss <® f m isarEHsOT OF mm eoMPOHSRi of c o m i c muxmion,^ l o e
• -i CosBSic-say I m t m m a t Ouljaarg = 110
I n f l n s n c c of s m l l s o l a r f l a r e s on t h e laeson I n t e s i s i t y recorded a t h i ^ ^ r geotaagmtic l a t i t t i d e s 113
GHAPfSE
B W m OP f l ® CHAMCfSR OF COailC RA£ INTEHSITY VARIA130H BURIHG SaMB AB0 MAGNETIC Dl^RMf?CES» 120
7 . 1 Method of a n a l y s i s 122
7 . 2 A s s o c i a t i o n between th© d a i l y mean meson I n t e n s i t y and solas* f l a r e s fo l lowed and n o t folloyred l>y laagoet lc-s tojans 122
7«3 V a r i a t i o n of c o a a l e r a y mason i n t e n s i t y w i t h s o l a r f l a r & s . ( fo l lowed a a g n e t i c - s t o r m s ) a t d i f f e r e n t M t l t a d e s .124
7*4 4 s s o c l a t i c m m r i a t i o n s o f meson iGrt^ansity ana t h e i m p o r t a n i s of t3ie s o l a r f l a r e s
7*S H e l a t i o n s h i p betwesn tha v a r i a t i o n s of meson I n t e n s i t y and t h e snn-apo t a e t i " ^ t y 130
7 . 6 R e l a t i o n s h i p between s s a l l s o l a r f l a r e s and gecHoagnetie d l s t t i rbanees 132
Vll
Tim d o l a y Irstwaen t h e oecuweiiQe of a s o l a r f l a r e and tii© s t a r t of tha a s s o c i a t e d
7mB D i s c u s s i o n ^ d in te?s ) i?a ta t ioa of e x p e r t a e n t a l r e s i i l t s 134
APPSmX I
APPiaiDlX I I 150
APPENDIX I I I . 1 5 2
1
c h a p t e r — I .
A good dea l of work 021 t ime v a r i a t i o n
of c o a a i c - r a j i a t e n a i t y , u s i n g i o n i s a t i o n diambers
and coun te r t e l e s c o p e s , h a s oeen r e p o r t e d i n the
l i t e r a t u r e ^ . I n r e c e n t y e a r s , n e u t r o n s jojai tors and
s c i n t i l l a t i o n c o u n t e r s have a lao been employed i n
the stu<^y of t i m e - i r a r i a t i o n of cosmio - r aya . I t
h a s cose t o ^ r e a l i s e d t h a t fromjfche study of t i m e -
v a r i a t i o n of cosjaaic-rgys mudi c ^ be l e a r n t d i r e c t l y
about t h e mechaniam o f ^ t h e i r p r o d u c t i o n , "to-eir
o r i g i n and p r o p a g a t i o n to t h e ea i ' t h , and a lso a\J0ut
the v a r i o u a i n f l u e n c e s on them a r i s i n g from the
e l e c t r o m a g n e t i c c o n d i t i o n s of i n t e r p l a n e t a r y space
and of the Sun. I n view of t h i a impor t ance , the
I n t e r n a t i o n a l Greophysical Year i n c l u d e d
i n i t s programme t h e study of t i m e - v a r i a t i o n of the
h a r d component of cossa ic- rays oy means of s t a n d a r d i z e d
cubical-me son t e l e s c o p e s . Neutron m o n i t o r s and a l so
i o n i z a t i o n chaffi-bers were o p e r a t e d a t v a r i o u s s t a t i o n s
sp read th roughou t the •Korld dur ing t h e I . Q . Y . progrsBaaa©,
1 . H . E l l i o t , p r o g r e s s i n Cosmic-ray P h y s i c s , ? o l . I , 4 5 5 , ( 1 9 5 2 ) .
I n t h i s t h e s i s d a t a c o l l e c t e d a t Gulsa rg
have been u t i l i z e d , ba t -Hae r e s u l t s o b t a i n e d a t o t h e r
s t a t i o n s have a l so beezi a n a l y s e d ^^iaere nf ioessary ,
&xilmarg d a t a was c o l l e c t e d b j a c o a b i n a t i o a of f o u r
t e l e s c o p e s » a c u b i c a l t e l e s c o p e , and w i t h i n i t
1 4 , 5 ^ , 7® and 4® t e l e s c o p e s .
33AILY YARlAflOH
Most of the c o s m i c - r ^ i n t e n s i t y Y a r i a t i o n s
obse rved a t s e a - l e v e l a re due t o a tn jospher ic e f f e c t s .
Ihen t h e s e e f f e c t s have been el iminatfed a omall d a i l y
v a r i a t i o n r ema ins . Tq e l i m i n a t e the e f f e c t of
a tmospher ic px^easure caad t e m p e r a t u r e on cosiaic-r^y 2
i n t e n s i t y , IXiperier i n v e s t i g a t e d a r e l a t i o n of t h e
t y p e .
AI « p> Ap + V A t
^ e r e - a j , ^ p , and ^ t r e p r e s e n t v a r i a t i o n s
i n cosifiic-ray i n t e n s i t y , ba rome te r ! c p r e s s u r e and
a tmospher ic t e m p e r a t u r e . Suda a t t e m p t s d id n o t , however,
always r e s u l t i n e o n a s t e n t v a l u e s f o r t h e p r e s s u r e
and t empera tu re c o e f f i c i e n t |2>snd V mainly because
the cho ice of the v a r i a b l e A t «as r a t h e r ambiguous
2 . A. B u p e r i e r , Hature 158, 196 ( 1 9 4 6 ) .
as i t was d i f f i c u l t to as^r wtiich p a r t of t h e atmosphere
should fee cons ide red f o r i t s t e m p e r a t u r e v a r i a t i o n s .
R e c e n t l y , IhrmsxiP and o t h e r s have sugges ted
t h a t i ( i ) f o r t he p r e s s u r e c o e f f i c i e n t p , one i ^ou ld
u s e a s t a n d a r d v a l u e which can he t h e o r e t i c a l l y
e s t i m a t e d ; ( i i ) f o r c a l c u l a t i n g t h e t e m p e r a t u r e
e l l e c t s , one slaould e-valuat^ i l^s e o n t r i b ' a t l o n t r o a
d i f f e r e n t l a y e r s of t he atmosphere s e p a r a t e l y .
A p r e c i s e knoT/ledge of t h e a tmospher ic c o n d i -
t i o n s to.ring the pe r iod of o b s e r v a t i o n i s r e q u i r e d
t o c a l c u l a t e t h e e f f e c t mentioned i n ( i i ) . 31his i s
d i f f i c u l t to o b t a i n . I n t h e case o f smal l a p e r t u r e
t e l e s c o p e s the c o a n i c - r a y v a r i a t i o n s a r e of t h e o r d e r
of l i b - c^t hence d a t a i s a lmost u n a f f e c t e d by
t e m p e r a t u r e . I n the c a s e of n e u t r o n moni to r d a t a ,
t he t empera tu re e f f e c t i s i n B i g n i f i c a n t said b a r o m e t e r i c
p r e s a i r e e f f e c t i s ve ry we l l known. Shus both t h e s e
t y p e s of ins t r t i i aen t s , namely na r row-ang le t e l e s c o p e s
and n e u t r o n m o n i t o r s can be e f f e c t i v e l y employed i n
the s tudy of t ime v a r i a t i o n .
Pur the rmore , r e a l i z a - t i o n h a s sroT.7n i n r e c e n t
3 . L . I . Dorman, Gosmic-ray v a r i a t i o n s (1957) ; „
y e a r s t h a t tho s o l a r a n i s o t r o p y of cos tn io-rays i s
of a h i ^ l y Yariatele c toarac ie r^*^ . S i i s char a s t e r
of t a e s o l a r a n i s o t r o p y has been s t u d i e d Xn t he
p a s t by oae or two workers by measur ing tiia s o l a r
d a i l y v a r i a t i o n du r ing the p e r i o d of sd-EiaHMi a o l a r
a c t i v i t y on ly a t low l a t i t u d e s , f h e s o l a r and
t e r r e s t r i a l r e l a t i o n s a i g s of ti ie d i anges of a n i s o t r o p y
have a l s o Deen s t u d i e d p r e v i o u s l y and t i i e o r i e s have
been advaaoed to e z p l a i n the c r e a t i o n of Hie a n i s o t r o p y
by a modu la t i on mechanism* A c o n f i r m a t i o n of t h e s e
expe r imen ta l o b s e r v a t i o n s and proposed models i s of
c r u c i a l s i g n i f i c a n c e to t h e t h e o r i e s of t he o r l ^ n
of c o a a i c - r a y s and of the e l e c t r o m a g n e t i c c o n d i t i o n s
of i n t e r p l a n e t a i ^ space . Hence i t was dec ided to c a r i y
out an exper imenta l s tudy a t a middle l a t i t u d e and
h i ^ a l t i t u d e s t a t i o n dur ing t h e y e a r of mazismm s o l a r
a c t i v i t y , f h e meaairements were c a r r i e d o u t a t
Gulmarg ( X « 24.7®Br» 9000 f t . ) by means of t h r e e
na r row-ang le t e l e s c o p e s hav ing s e m i - a n ^ e s of
and 14^5°. I n our view t h i s s tudy would compliment
the e a r l i e r low l a t i t u d e s t u d i e s dur ing y e a r s of
ainiffium s o l a r a c t i v i t y » ^hus oar study may h e l p i n
e s t a b l i s h i n g a more c o n s i s t e n t t heo ry of t h e
4 . Y-Sarabhai and H.W. Keru rka r , Annuiil S e v . S u c l e a r , S c i . , 6 , 1 , (1958) .
5
e l e c t r o m a g n e t i c c o n d i t i o n s i n ttie i n t e r p l a n e t a r y
space and t h e o r i g i n of cosmic-raya»
Simpson and o t h e r s have shown tha t - . t he diurned
v a r i a t i o n of the n e u t r o n component i s n e a r l y t h r e e
t i m e s t h a t of t h e h a r d component. O b s e r v a t i o n s on the
h a r d (^mponent of t he 0 3 s m i c - r a d i a t i o n a t s e a - l e v e l
p rov ide i n f o r m a t i o n on the energy p a r t of the
primary cosmio-ray beam. I n f o r m a t i o n on t h e low
energy p a r t of t h e &eam may be o b t a i n e d a t s e a - l e v e l
by s tudy ing t h e i n t e n s i t y of the n e u t r o n component,
2hus , f o r \ i n d e r s t a n d i ^ t h e energy spectrum of t h e
pr imary a n i s o t r o p y , a very i m p o r t a n t t o o l i s the s tudy
of t h e SEpl i tude and phase of t h e d a i l y v a r i a t i o n of
cosmic-ray meson and n e u t r o n i n t e n s i t y a t d i f f e r e n t
l a t i t u d e s .
5 E a r l i e r r e s u l t s of Thompson (1958) * Lange
and Forbush (194a )^ , ThambyahpillaL and E l l i o t (1953)"^ 8
and F i r r o r e t* a l . (1954) have shown t h a t t h e
ampl i tude of the dixirnal v a r i a t i o n of t h e mason and
3. J.L.Thompaoii, Phya. Rev . , 93 (133S) . 6 . I ,Lange and S .B.Porbush, Carnegie I n s t i t u t e of
Washington, P u b l i c a t i o n 175 (194-8). 7 . f h a m b y a p i l l a i and E . E l l i o t , ITature, 171^918(1953)* 8 . J . A . P i r r o r , l . H . fonge r and J .A.Simpcon, p h y s . R e v , ,
£ 4 , 1051 ( 1 9 5 4 ) .
6
u e u t r o n eompO£.€nt <aoQs not dopand on gcorsagnetic
l a t i t i x a e s . But liie l a t i t u d e dependence of t h e
phase of t h e s e oomponents was not s t u d i e d l a Itoe
p a s t by t h e s e or o t h e r i n v e s t i g a t o r s *
'fhe e a r l i e r r e s u l t s were a l s o , not v e r j
s y s t e m a t i c between the r e g i o n from the e q u a t o r to
t h e po le i t i both t h e hemisphe re s . Cont inuous measure -
ments of meson and n e u t r o n i n t e n s i t y of coera ic- rays
d u r i n g t h e i n t e r n a t i o n a l Geophysical Year {1957-58)
sore i m p o r t a n t i n mgfeing a s y s t e m a t i c s tudy of t h i s
prohlem* Hence u s i n g Uie d a t a of meson smd n e u t r o n
i n t e n s i t y c o l l e c t e d dur ing the I . G . Y . a t l a t i t u d e s
from 75'^S to 83®R, se s t u d i e d ^ f s t e m a t i c a l l y the
l a t i t u d e dependence of ampl i tuds and phase of the
d i u r n a l comporiant i n both the h e m i s p h e r e s , Using
the same d a t a we a l so examined the a l t i t u d e dependence
of tiie ampl i tude and phase* By t h i s s tudy an i m p o r t a n t
r e s u l t fSaich we oboerved f o r the f i r s t time i s t h a t
t h e phase of the d i u r n a l v a r i a t i o n d e c r e a s e s a s t h e
l a t i t u d e i n c r e a s e s i n the n o r t h e r n hemisphere . But
a ich a n a t u r e of phase was no t observed i n the sou-
t h e r n hemisphere .
1 . 2 SOLAK FLAKE BPfECf OM COSMIC-BAY IMTEMSITI
I n t h e l a s t few y e a r s a t t e n t i o n of s e v e r a l
7
i n v e s t i g a t o r s h a s been a t t r a c t e d by t h e cosmic - r ay
i n c r e a s e s a s s o c i a t e d vvlth. s o l a r f l & r e s i raostj^y w i th
l a r g e s o l a r f l a r e s . Cosmic- ray v a r i a t i o n s of t h i s
c l a s s a r e e x t r e m e l y i n t e r e s t i n g s i n c e t h e y y i e l d
v j ^ u a b l e i n f o r m a t i o n abou t how low energy c o s m i c - r a y s a t
a r e g e n e r a t e d t h e s u a , and abou t p r o c e s s e s i n the
s o l a r a tmosphere , t h e i scopaga t ion of a c c e l e r a t e d
p a r t i c l e s t h r o u ^ the c o r o n a and t h e supe r co rona
of t h e aan, and about p r o p a g a t i o n i n i n t e r p l a n e t a r y
s p a c e .
Uar ing t h e p a s t s e v e n t e e n y e a r s t h e r e have
been f i v e l a r g e cosmic - ray i n c r e a s e s a s s o c i a t e d
wi th t h e o c c u r r e n c e of l a r g e s o l a r f l a r e s ^ * ^ \saaich
have been o b s e r v e d d i r e c t l y . Ihe laoat i n t e n s e of
t h e s e , on 23rd f e b . 1956, r e s u l t e d i n 50 f o l d
i j a c r ea se of t h e i n t e n s i t y of t h e p r i a a r y r a d i a t i o n
i n iiie energy r e g i o n 1 - 1 0 Bevj and a 5 f o l d i n c r e a s e
i n t h e re^^ion of 10-1000 Bev. I t was e l s o p o s s i b l e
to ^ o w t h a t the p a x ' t i c l s s csne f rom the s a n , t h a t
t h e i r mean energy was about 4 Bevj and t h a t they were
p r edominan t ly p r o t o n s .
I t h a s been obse rved t h a t s m a l l e r i n c r e a s e s
a r e o f t e n a s s o c i a t e d -with the s m a l l e r s o l a r f l a r e s ,
8
anSd the ave rage i m e r e a s e i s of o r d e r of a
few p e r c e n t . S ince on ly a few s t u d i e s Have been
made i n t h i s d i r e c t i o n , i n o r d e r to e x t e n d such
i n f o r m a t i o n we a n a l y s e d d a t a f rom t h r e e h i ^ l a t i t u d e
s t a t i o n s . We o b s e r v e d an i n c r e a s e i n meson i i i t e n ^ t y
on 19 th J u n e , 195S, a t Sulmarg a s s o c i a t e d Ydth a
smal l s o l a r f l a r e o f i m p o r t a n c e 2 , r e p o r t e d by
KodgdkG»al S o l a r O b s e r v a t o r y ( I n d i a ) . We a l s o exao ined
t h e average e f f e c t of s m a l l s o l a r f l a r e s of impor t ance
1 and 2 on cos ia ic - ray i n t e n s i t y by p e r f o r m i n g a
s t a t i s t i c a l s t u d y -
1 . 5 MAgMiaiC SfOBMS ASSOCIATED VITH SOLAR gLARllS
f h e s t u c ^ of c o a n i c - r e y d e c r e a s e s a s s o c i a t e d
v d t h m a g n e t i c s torms i s i m p o r t a n t fro/a t h e p o i n t ot
view of u n d e r s t a n d i n g tho g e n e r a l p i c t u r e o f c o a a i c -
r a y m o t o l a t i o n i n t h e s o l a r sy s t em. S h i s study i s
a l eo u s e f u l , because i t p r o v i d e s Viiluable i n f o r m a t i o n
to u n d e r s t a n d t h e e l e c t r o m a g n e t i c c o n d i t i o n s of
t h e corpUGCttlar streams e j e c t e d from tne sun and
t h e i r i n t e r a c t i o n Yiith t h e i n t e r p i aMetai-y mediiin and
the e a r c h .
f l a i l i e r s t u d i e s de^^oted to t h e e f f e c t s 9 . L . I . Dorm an, p r o g r e s s i n e l e m e n t a r y p a r t i c l e ana
cosmic - r ay p h y s i c s , Vol. ? i l , ( 1 9 6 3 ) . 1 0 . p r o c e e d i n g s of the Moscow Cosraic-rOT Conference
V o l . 4 , ( 1 9 6 ^ ) .
9
of magne t i c s to rms on cosmic - ray i n t e n s i t y were
main ly based on l a r g e s to rms , hence we thougbit i t
wor thwhi le t o s t u d y t h e c h a r a c t e r of t h e p r o f i l e
of t h e cosmic - r ay d e c r e a s e s wi th magne t ic s to rms
which f o l l o w s o l a r f l a r e s * Por t h i s purpose
we s e l e c t e d t h r e e i i i ^ l a t i t u d e s t a t a t i o n s and a n a l y s e d
t h e d a t a c o l l e c t e d t h e r e di i r ing t h e I . G . Y . p e r i o d .
T h i s b e i n g a l s o t h e p e r i o d when t h e f r e q u e n c y of
o c c u r r e n c e of such magne t ic s to rms was s u f f i c i e i s t l y
l a r g e . We b e l i e v e , our s tudy w i l l be h e l p f u l i n
p r o v i d i n g i n f o r m a t i o n about t h e way t h e e a r t h e n t e r s t h e
s t r eam, t h e v e l o c i t y of t h e s t ream and the d i s t r i b u t i o n
of t h e f i e l d i n i t . I t w i l l a l s o p rov ide a check t o
examine t h e e x i s t i n g models and t h e o r i e s ;(?Siich were
main ly proposed t o e x p l a i n t h e f e a t u r e s of l a r g e cosmic-
r a y d e c r e a s e s d u r i n g t h e l a r g e magnet ic s torms) con-
ce rn i i j g cosmic- ray d e c r e a s e s d u r i n g magne t ic s to rms
a s s o c i a t e d wi th smal l s o l a r f l a r e s .
1 . 4 SCHEME Of THESIS
She work which we d i d on d i f f e r e n t a s p e c t s
of t i m e - v a r i a t i o n of cosmic- ray i n t e n s i t y , i s p r e s e n t e d
i n t h i s t h e s i s i n t h e f o l l o w i n g o r d e r
10
I n t h e second c h a p t e r t he c o n s t r u c t i o n and
w j r k i n g of t h e meson c u b i c a l t e l e s c o p e a long witii
t h e t h r e e nar row-angle t e l e s c o p e s i s g iven i n d e t a i l ,
f h e e l e c t r o n i c c i r c u i t s which ^e des igned f o r our
purpose a re a l l b a t t e r y o p e r a t e d and baaed on
m i n i a t u r e tubes« f h e s e a re a l s o d i s c u s s e d i n t h i s
c h a p t e r .
I n t h e t h i r d c h a p t e r t h e d i u r n a l v a r i a t i o n of
c o a a i e - r a y meson i n t e n s i t y and i t s r e l a t i o n to t h e
magnet ic c h a r a c t e r f i g u r e Cp and sunspo t numbers i s
s t u d i e d . £he v a r i a b l e c h a r a c t e r of t h e s o l a r a n i s o t r o p y
i s a l s o examined by s tudy ing t h e day to day changes i n
t h e d i u r n a l v a r i a t i o n of cosmic - ray i n t e n s i t y r e c o r d e d
by na r row-ang le t e l e s c o p e s .
I n the f o u r t h c h a p t e r t h e l a t i t u d e and a l t i t u d e
dependence of the ampl i tude and phase of t h e d i u r n a l
and the s e m i - d i u r n a l v a r i a t i o n of cosmic- ray meson and
n e u t r o n i n t e n s i t y i s s t u d i e d .
The f i f t h chap t e r d e a l s wi th a s y s t e m a t i c s tudy
of t h e n a t u r e of t h e d i u r n a l and" s e m i - d i u r n a l v a r i a t i o n
of meson a s we l l a s n e u t r o n i n t e n s i t y on m a g n e t i c a l l y
q t i ie t and d i s t u r b e d days a t d i f f e r e n t l a t i t u d e s i n both
t h e hemisphe res .
11
She s i x t h c h a p t e r d i s c u s s e s t h e e f f e c t of
small s o l a r f l a r e s on cosmio-ray meson i n t e n s i t y .
"the seven th c h a p t e r t h e c h a r a c t e r of t h e
cosmic r a y i n t e n s i t y v a r i a t i o n s d u r i n g the magnet ic
d i s t u r b a n c e s a s s o c i a t e d with smal l s o l a r f l a r e s i s
s t u d i e d .
1 . 5 IMPORgAHT RESPLSS :
Some of t h e i m p o r t a n t and i n t e r e s t i n g r e a i l t s
which we found i n our s tudy d u r i n g the y e a r of
maximtua s o l a r a c t i v i t y a re l i s t e d below i
( i ) f h e ampl i tude of the d i u r n a l and s e m i - d i u r n a l
components of meson as we l l a s n e u t r o n i n t e n s i t y does
not show any s y s t e m a t i c l i n e a r r e l a t i o n s h i p with
l a t i t u d e . But a t p o l a r , s t a t i o n s t h e ampl i tude of t i e
d i t i rna l v a r i a t i o n i s a p p r e c i a b l y sma l l e r t han a t o t h e r
s t a t i o n s .
Another very ^ g n i f i c a n t p o i n t obse rved i s t h a t
f o r t h e meson i n t e n s i t y i n t h e n o r t h e r n hemisphere ,
t h e d i u r n a l and s e m i - d i u r n a l smpl i tude a t f i r s t
increase^sd- th l a t i t u d e , bu t the t r e n d i s r e v e r s e d a t
about a l a t i t u d e of the r e a s o n f o r t h i s s t r a n g e
behaviour h a s y e t t o be found .
12
( i i ) f h e pbase of t h e d i u r n a l v a r i a t i o n of cosmic-
r a y meson and n e u t r o n i n t e n s i t y d e c r e a s e s a s t h e
geomagnetic l a t i t u d e i n c r e a s e s i n the n o r t h e r n
hemisphe re . But such a hehavioi ir of phase with
l a t i t u d e i s not found i n the s o u t h e r n hemisphere .
( i i i ) Th i s l a t i t u d e dependence of phase of t h e
d iuxna l v a r i a t i o n remains u n a f f e c t e d on d i s t u r b e d
and q u i e t days .
( i v ) The phase of the s e m i - d i u r n a l v a r i a t i o n of
coamic- ray meson as we l l a s n e u t r o n i n t e n s i t y does not
bear any s y s t e m a t i c l i n e a r r e l a t i o n wi th geomagnet ic
l a t i t u d e s i n bo th the hemisphe re s . But on m a g n e t i c a l l y
q u i e t days t h e phase of both the meson snd n e u t r o n
i n t e n s i t i e s d e c r e a s e s with l a t i t u d e i n the n o r t h e r n
hemisphere o n l y .
(v) The phases of t h e d i u r n a l and s e m i - d i u r n a l
components of t he d a i l y v a r i a t i o n s occur e a r l i e r a t
h ig j i e r a l t i t u d e s . IThis i s found f o r both t h e meson
and n e u t r o n i n t e n s i t y phase s .
( v i ) The average d a i l y v a r i a t i o n of t h e n e u t r o n
i n t e n s i t y on m a g n e t i c a l l y d i s t u r b e d days a t d i f f e r e n t
l a t i t u d e s i n both the hemispheres , h a s tv?o maxima
13
and two miQima. file i m p o r t a n t po in t wiaicla<4s o b s -
e rved by u s i s t h a t tiie geSieral n a t u r e of t h e d a i l y
v a r i a t i o n of n e u t r o n i n t e n s i t y i n the n o r t h e r n hemis -
phere i s o p p o s i t e to t h a t of t h e d a i l y v a r i a t i o n
i n t h e s o u t h e r n hemisphere .
< v i i ) On q u i e t days t h e average d a i l y v a r i a t i o n s
of meson and n e u t r o n i n t e n s i t y g e n e r a l l y have on ly
one mazima and one minima.
I t i s a l so foiind t h a t t he gene ra l n a t u r e of
the d a i l y v a r i a t i o n of meson and n e u t r o n i n t e n s i t y
i s s i m i l a r a t d i f f e r e n t geomagnetic l a t i t u d e s i n
t h e n o r t h e r n hemisphere , but i t i s not so i n t h e
sou the rn hemispheres .
( v i i i ) On 19th of June 1958 we obse rved an
i n c r e a s e of meson i n t e n s i t y a s s o c i a t e d wi th a s o l a r
f l a r e of impor tance 2. This i n c r e a s e was d e t e c t e d
with t h r e e t e l e s c o p e s l i av ing s emi -ang le s 4®, 14.5®
and 45° ( c u b i c a l ) , and i t was 41.29+5.27^,17.23+3
19.36+0.50?^ r e s p e c t i v e l y .
( i x ) I n t h e case of f l a r e s f o l l o w e d by magnet ic
s to rms , vre found t h a t the average meson i n t e n s i t y
i n c r e a s e s even b e f o r e t h e f l a r e day. The maximum
14
i n c r e a s e i s about 0 .17+0-056^ a t about two days b e f o r e
t h e f l a r e day. A f t e r t he f l a r e , t h e i n t e n s i t y f a l l s
below i t s average v a l u e , and r e a c h e s the minimum
vsO-ue -0 .24+0 .056^ t h r e e days a f t e r t he f l a r e .
But i n t h e case of f l a r e s not fo l l owed by mag-
n e t i c s torms , t h e meson i n t e n s i t y shows a t r e n d which
i s i n phase o p p o s i t i o n to t h e case j u s t d i s c u s s e d .
Average i n t e n s i t y shows a minimum of about - 0 . 8 1 + 0 « 0 4 ^
n e a r l y two days p r i o r t o the f l a r e . I t r e t u r n s to
normal v a l u e , and t hen i n c r e a s e s t o about 4'0.31+0«04-25&
two to t h r e e days a f t e r t h e f l a r e .
(x) Another po in t r e g a r d i n g t h i s dec rease i s t h a t
the ampl i tude of t h e dec rease ( c a l l e d dip) of t h e
meson i n t e n s i t y observed a f t e r t he f l a r e cay ( o n l y
i n case of f l a r e s f o l l o w e d by magne t i c s torms) does
not show any l a t i t u d e dependence. However, t h i s d ip
o c c u r s l a t e r a s t h e geomagnetic l a t i t u d e i n c r e a s e s -
I t i s a l s o obse rved t h a t t h i s d ip becomes more and
more sha l low as t h e po le i s approached. This i n d i c a t e s
t h a t t h e p r o f i l e of the d ip and i t s time of o c c u r r e n c e
a re r i g i d i t y dependent .
( x i ) This c o a a i c - r a y decrease ( d i p ) i s a l so of
world-wide n a t u r e .
( s i i i ) Ihe magnitude of t i i i a dec rease i s
l a r g e r f o r magne t ic s torms a s s o c i a t e d wi-Hi f l a r e s
of impor tance 2 , tliiin f o r t h o s e a s s o c i a t e d witii
f l a r e s of impor tance 1 .
15
CHAggBi . - I I .
EliMilMESgAL ASaASaMEHS
2 . 0 We s h a l l mw d e s c r i b e t h e equipment which
was u sed f o r c o l l e c t i n g t h e c o s a a i c - r ^ meson i n t e n s i t y
d a t a a t Golmarg, p a r t l y d u r i n g t h e IQX programme.
Gulmarg i s a h i l l s t a t i o n a t a h e i g h t of 9000 f t . , and
a geomagnet ic l a t i t u d e of 2 4 . 7 ° S . The Gulmarg Resea rch
O b s e r y a t o r y i s s i t u a t e d on a h i l l c l e a r of a l l s u r r o u n -
d i n g s , and communicat ion w i t h t h e O b s e r v a t o r y i s ve ry
d i f f i c u l t , e s p e c i a l l y d u r i n g t h e w i n t e r months . The
d i e s e l e l e c t r i c supply i s no t f u l l y dependab le when
d a t a h a s t o be c o l l e c t e d w i t h o u t a b r e a k .
I n view of t h i s d i f f i c u l t y , a l l t h e e l e c t r o n i c
c i r c u i t s had t o be d e s i g n e d f o r b a t t e r y o p e r a t i o n and
c o n s e q u e n t l y m i n i a t u r e t u b e s were u s e d . We d e s i g n e d t h e
quisnching, c o i n c i d e n c e , d i s c r i m i n a t o r and t h e s c a l e r
C i r c u i t s .
The c o u n t e r s u sed were a l s o c o n s t r u c t e d
i n t h e l a b o r a t o r y of t h e Depar tment of P h y s i c s , A l i g a r h
Muslim U n i v e r s i t y , i a i g a r h .
Details of a l l t h i s equipment a r e g i v e n below
2 . 1 &-M. GOOBTaES
. S ^ f - q u e n c h i n g S-M c o u n t e r s were u s e d w i t h
17
dimensions shown i n f i g . 1 . Pyrex ^ a s s envelope
had an o u t s i d e d iameter of 1*63 i n c h and a t h i c k n e s s
of 0 . 0 6 i n c h , f h e e f f e c t i v e l e n g t h of t h e copper
ca thode was 23.0 i n c h e s and i t s d iamete r was 1 . 5 i n c h ,
fmngs tun anode of 3 m i l d iameter was u s e d . An
a p p r o p r i a t e a p p a r a t u s f o r e v a c u a t i o n and gas f i l l i n g
was s e t up .
2 . 2 QOgSfEUCflQH Qg THE gSLESGOPE
The meson c u b i c a l t e l e s c o p e # i i c h was cons -
t r u c t e d a t Gulmarg Research O b s e r v a t o r y was s i m i l a r
t o t h e s t a n d a r d meson c u b i c a l t e l e s c o p e recommended if
by t h e ooamic-ray sub-commit tee of t h e i n t e r n a t i o n a l
Union of Pure and Appl ied p h y s i c s to s tudy the t i m e -
v a r i a t i o n of meson i n t e n s i t y i n t h e lower atmosphere
d u r i n g t h e I n t e r n a t i o n a l Geophysica l y e a r 1957-58.
The arrangement of c o u n t e r s w i t h t h e i r
a s s o c i a t e d e l e c t r o n i c u n i t s i s shown i n schemat ic form
i n f i g . 2 . The t e l e s c o p e c o n s i s t e d of f o u r t y f i v e
GrH5$ c o u n t e r s and t h e s e were a r r anged i n t h r e e t r a y s
^diich were e l e c t r o n i c a l l y coupled i n t r i p l e co inc idence
a r rangement . The t r a y s were aarranged one above t h e
o t h e r and t h e top and bottom t r a y s were s e p a r a t e d by
a d i s t a n c e of 25 i n c h e s . The c o u n t e r s were p l a c e d
Copper Cylino<R 5v«tl ToM&'STrvj Seoil off, cxfif' I'ltK'K wilh M -VXUT'
Glass Envelope 23
Glass slmm
Fx l GLA;,S ENVELOPE G-M. COUNTER
^ 3
V t/N/T e ^COWC/Ot/VCi i/MT D iD/SC/l/M/N^TO/^ S --.SCf/l£ft
O/" G./yr. CO(/Afrs/?S M^/r^ t^S/^ /^SJOCtfiTED £L£CT/?0N/C OAf/TS.
18
With t h e i r axes p a r a l l e l t o t h e E-?? p l a n e , t h e
t e l e s c o p e hav ing a semi -ang le 45® i n the E-W p l a n e
a s v?ell a s i n t h e S-S p l a n e .
fwo s l a b s of l e a d , each 5 cm. t h i c k , were
p l a c e d bettf/een t h e co imte r t r a y s i n o r d e r t o c u t o f f
t he / so f t component, and a l low e s s e n t i a l l y t h e jkLmesons
t o be r e c o r d e d .
S h ^ h o l e of the t e l e s c o p e t o g e t h e r ?.'lth t h e
h igh t e n s i o n b a t t e r i e s was enc losed i n a t empe ra tu r e
c o n t r o l l e d c a b i n e t m a i n t a i n e d a t 2 7 ^ 1 ^ 0 . 2he temper -
a t u r e of t h e c a b i n e t was ma in t a ined wi th t h e h e l p of a
mercury the rmo- reguXator .
f h e average coun t ing r a t e of t h e t e l e s c o p e was
about 45fOOO t h r e e f o l d c o i n c i d e n c e s per h o u r , f h e
count was r e c o r d e d a t h o u r l y i n t e r v a l s by pho tog raph ing
t h e t e l e p h o n e c a l l r e c o r d e r . Between t h e r e c o r d e r azui
t h e t r i p l e co inc idence c i r c u i t t h e r e was a s c a l i n g f a c t o r
of 128.
Leav ing a s i d e t h e end c o u n t e r a s an independen t
quenched u n i t t h e r e s t of t h e f o u r t e e n c o u n t e r s were
d iv ided i n t o seven s e t s of two c o u n t e r s each, and each
s e t of two c o u n t e r s was connected to one quenching u n i t .
I n t h i s w ^ e i ^ t quenching u n i t s (Q) were put i n each
t r a y a s shown i n f i g . 2 . f h e p u l s e s from t h e s e quenching
19
u n i t s were connec ted l a p a r a l l e l and f e d t o t i ie
c o i n c i d e n c e u n i t (C) , which i n c o n j u n c t i o n wi th t h e
d i s c r i m i n a t o r (B) s u p p l i e d t r i p l e c o i n c i d e n c e p u l s e s
t o t h e s c a l e r ( 3 ) .
2 . 3 ABEASGMEHg FOfi HASROy«AH&L£ g£L£SOQP£S
f h e c u b i c a l t e l e s c o p e d e s c r i b e d above was
d i v i d e d i n t o t h r e e na r row-ang le t e l e s c o p e s , P i g . 5 ( a ) ,
hav ing s emi - ang l e s 4®, 7° and 14.5^ i n t h e H-S p l a n e
and 45® each i n the E-W p l a n e . I t may be noted t h a t
t h e s e t e l e s c o p e s c o n s i s t e d of one» two and f o u r
c o u n t e r s e a c h .
Three s e p e r a t e co inc idence u n i t s were employed
f o r t h e s e n a r r o w - a n ^ e t e l e s c o p e s and t h e o u t - p u t of
t h e c o i n c i d e n c e d i s c r i m i n a t o r combina t ion of each c i r c u i t
was r e c o r d e d s e p e r a t e l y a f t e r i n t r o d u c i n g a s c a l e of f o u r ,
P ig , 5 ( b ) . !I?he t e l e p h o n e c a l l r e c o r d e r s connected w i th
t h e narrow ang le t e l e s c o p e s were a l s o pu t nea r t h e main
r e c o r d e r f o r be ing piwDtographed every h o u r .
2 . 4 ' ELECfRQHIC ClBCmiES
I h e quenching u n i t s and the c o i n c i d e n c e u n i t s ,
which were wired on t h e s ^ e c h a s s i s were p l a c e d oh
t h e coun t e r t r a y s , whi le t h e s c a l e r s and the power
s u p p l i e s were p u t i n a s e p e r a t e c a b i n e t shown i n
photograph 1 .
cocoDooocooqocp
3r«>.
<y oc/sTAX/VAvtr ^i^/r C OOMCi OfAY t/ /T D ZWCWf nw*/* J TCtt^fjt €3X- ^ A* •rtrWWA'V -
riC 3 UK - /^A^eir rrin cor£ ;
1 -
io JLt
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f h e c o u n t e r s were checked from t h e back
door of t h e t e l e s c o p e c a b i n e t toy t a k i n g t h e c o u n t i n g
r a t e of t h e i n d i v i d u a l c o u n t e r s wi th the h e l p of a
coamerc i a l s c a l e r , and the p u l s e s were checked on an
o s c i l l o s c o p e . I h e t e s t i n g of the c o u n t e r s was done
every morning and n i ^ h t .
I n t ime v a r i a t i o n expe r imen t s where r e l i a b l e
o p e r a t i o n of t h e c o u n t e r s o v e r a l ong p e r i o d of t ime i s
e s s e n t i a l , t h e u s e of quenching u n i t s improves t h e f l a t -
n e s s of t he p l a t e a u and p r o l o n g s t h e l i f e of t h e quenched
c o i m t e r s by s u p p r e s s i o n of m u l t i p l e d i s c h a r g e s , t h e r e -
f o r e , a quenching c i r c u i t , f i g . 4, was u s e d .
I n o r d e r to s i m p l i f y t h e w i r i n g , conse rve
power from t h e b a t t e r i e s and minimize p u l s e a t t e n u a t i o n , n
t h e quenching and c o i c i d e n c e u n i t s were wired on t h e A
same c h a s s i s . SPhe c o i n c i d e n c e c i r c u i t f o r t h e c u b i c a l
t e l e s c o p e and t h e n ^ r o w - a n g l e t e l e s c o p e s a r e almost
thejsame except f o r the g r i d r e s i s t a n c e which i s d i f f e r e n t
i n t h e %m c a s e s , f h e c i r c u i t diagram i s shown i n F i g . 5 .
The s c a l i n g u n i t c o n s i s t s of f i v e c i r c u i t s t ( i ) d i s c r i m i n a t o r , shown i n F i g . 6 , and ( i i ) p u l s e - s h a p e r
( i i i ) s c a l e r ( i v ) a m p l i f i e r and (v) Eecorder d r i v e shown
i n F i g . 7 . f h e c i r c u i t of t he s c a l e r used wi th t h e narrow
t e l e s c o p e s i s shown i n F i g . 8 .
t I J,/ i\ UvxKtHtwt. CiMcmf
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21
f h e p o s i t i v e p u l a e s from t h e c ^ c i d e n c e
c i r c u i t were f e d t o a d i s c r i m i n a t o r Dsiiose ou t p u t was
a square p o s i t i v e p u l s e c o r r e s p o n d i n g t o the conc iden t t\. e v e n t , f h i s p u l s e was g iven a c o r r e c t shape to s u i t
t h e s c a l i n g c i r c u i t vfeich r e q u i r e d 4 - v o l t n e g a t i v e
p u l s e s t o o p e r a t e s a t i s f a c t o r i l y . The s c a l e r could 5
f u n c t i o n p r o p e r l y when i t r e c e i v e d upto 2x10 p u l s e s
p e r second. 2hQ o u t p u t of the s c a l e r was a m p l i f i e d and
i t o p e r a t e d t h e mechanica l r e c o r d e r ,
ajhe n e g a t i v e v o l t a g e of ahout - 900 v o l t s
which was a p p l i e d a t t h e ca thode of t h e G-M c o u n t e r s was
t a k e n from Miniaax type Eveready dry b a t t e r i e s . I h e u n -
r e ^ i l a t e d D-C v o l t a g e of about 200 v o l t s was p rov ided
by a l k a l i c e l l s and t h e r e g u l a t e d •¥& v o l t a g e s , t o a l l
the e l e c t r o n i c c i r c u i t s ment ioned above were s u p p l i e d
th rough a v o l t a g e r e g u l a t o r t u b e .
2 . 5 mOTOQUABElC AafiAHGMDHf
f h e pho tog raph ic ar rangement i s shown i n jPig.9«
HhQ f o u r t e l e p h o n e c a l l r e c o r d e r s as wel l as t h e watch
and d a t e arrangement were f i x e d i n a wooden box. At one
end of t h i s box, t h e 55 mm. cgaiera was a t t a c h e d . Four 6
v o l t s b u l b s were f i x e d i n s i d e t h e wooden box t o p rov ide
the f l a s h fo3^ the p h o t o ^ a p h . Every hour t h e b u l b s were
l i g h t e d and a photograph of the r e c o r d e r s , watch and the
R E L A Y - I
TO MOTOR
CLOCK
RELAV-2
TO FLASH BULB 6V.
6V. BATTERY
TO M O T O R
o o o o o o e o CAMERA
TO M O T O R
FIG.9 P H O T O G R A P H I C ARRANGEMENT
22
d a t e was t a k e n . A f t e r f i v e minu te s t h e f i l m was wound
by a motor b r i n g i n g a f r e s h frame i n p o s i t i o n r eady f o r
t h e nex t exposu re .
f h e c lock waa c o r r e c t e d each day wi th the
Greenwich t ime s i g n a l r e l a y e d by jy.1 I n d i a Radio .
2 3
DIUHHAt VARIATION OP COSMia«RAY MBSOH
I n r e c e n t y e a r s r e a l i s a t i o n l ias grovm t h a t
accumiilat ioi i o f d a t a on t ime v a r i a t i o n of cosmio-ra^
i n t e n s i t y and i t s i n t e r p r e t a t i o n o a tiie b a s i s of
e l e c t r o d y n a m i c s and p l a s a a p h y s i c s i s an ex t remely
u s e f u l branch of stmdy, The s tudy of t ime v a r i a t i o n
of coamic- rays i a an e l e g a n t and ex t remely s e n s i t i v e
t o o l f o r p r o b i n g t h e e l e c t r o m a g n e t i c c o n d i t i o n s i n
t h e v i c i n i t y of t h e e a r t h and the sun, i n i n t e r p l a n e t a r y
space , and i n the ga l axy .
I t i s r e p o r t e d i n l i t e r a t u r e t h a t t h e d a i l y
v a r i a t i o n of cosmic- ray i n t e n s i t y i s compl ica ted by a
s u p e r p o s i t i o n of m e t e o r o l o g i e s and s o l a r e f f e c t s .
5?hecosmic-ray d a t a from i o n i s a t i o n chambers and c o u n t e r
t e l e s c o p e s a re d i f f i c u l t t o c o r r e c t f o r m e t e o r o l o g i c a l
e f f e c t s * However, t he d i r e c t i o n a l measurements of s o l a r
d i u r n a l v a r i a t i o n of coamic - rays , made by Malmfors (1949)^
and E l l i o t and Dolbear (1951) demonst ra ted c o n c l u s i v e l y
t h a t a s u b s t a n t i a l p a r t of t he obse rved v a r i a t i o n i s o f
non-meteoro logLcal o r i g i n . Ihey sugges ted t h a t an
a n i s o t r o p i c d i s t r i b u t i o n of pr imary c o s m i c - r a y s , o u t s i d e
t h e i n f l u e n c e of t h e geomagnetic f i e l d s , might be
1 . K.G. Malmfors , T e l l u s , i , 55 (194-9).
2 . H . E l l i o t , and D.W.H. Dolbear , J .Atmos. l e r r . P h y s . I , 205, ( 1951 ) .
24
r e s p o n s i b l e f o r t h i s s o l a r di iarnal v a r i a t i o n . Burnberg 3
and Da t tne r (1954) s u b s t a n t i a t e d t h i s s u g g e s t i o n .
$he r e s u l t s o f E l l i o t and Eothwel l (1956)^
and P a r s o n s (1959)^ c a s t c o n s i d e r a b l e doubt on t h i s
p r o p o s i t i o n , However, t h e r e c e n t work of E l l i o t (1960)^
and Que^by and f h a m b y a h p i l l a i (1960)'^ h a s shown t h a t
t h e l e a r l i e r r e s u l t s of E l l i o t and Rothwel l and Pa r sons
can s a t i s x a c t o r i l y be accounted f o r i n terms of an .
e x t e r n a l a n i s o t r o p y of t h e p r i m a r i e s i f an a p p r o p r i a t e
c o r r e c t i o n i s a p p l i e d to t h e c o a a i c - r a y d a t a f o r t h e
d a i l y v a r i a t i o n o f a tmospher ic t e m p e r a t u r e . Hence, t h e
e x i s t e n c e of t h e d a i l y v ^ i a t i o n of cosmic- ray i n t e n s i t y
i s now u n i v e r s a l l y acknowledged, a l though t h e obse rved
v a r i a t i o n a t a ea l e v e l and a t mounta in a l t i t u d e s measured
by i o n i z a t i o n chambers and coun t e r t e l e s c o p e s i s l e s s
t h a n 15 of t he i n t e n s i t y .
Eecent advances i n the knowledge of t h e
r e l a t i o n between changes i n t h e pr imary and secondary
components { c a l l e d c o u p l i n g c o n s t a n t s o r s p e c i f i c y i e l d
f u n c t i o n s ) h a s g iven t h e s tudy of d i u r n a l v a r a i t i o n an
3 . E.A. Burnberg, iind A .Da t tne r , Mel ius , 6 , 73, and 6 , 254,. ( 1954 ) . ^^ ^
4 . H.El l iot , - - -and P .Ho thwe l l , P h i l Ma^. 669 (1956 ) . 5 . N.B. P a r s o n s , Aus t . - J . P h y s . , I S , 462 ( 1 9 5 7 ) . 6 . H. E l l i o t , P h i l . Mag., i , 601, ( i 9 6 0 ) . 7 . J . J . Quenby, and T. I h a m b y a h p i l l a i , P h i l . Mag. 585(1960
2 o
added impor tance i n t h e sense t h a t i f \r.e knoif t h e
d i u r n a l v a r i a t i o n of d i f f e r e n t components a t one p l a c e
or t h a t of t h e same component a t d i f f e r e n t l a t i t u d e s ,
we can f i n d ou t t h e changes i n t h e pr imary spectrum
r e s p o n s i b l e f o r t h i s v a r i a t i o n (Doriaan 1957)*®
3 . 0 1 CORRBO-IION gpH MEIEQ&QLOGIGAI. gACSORS
She d a t a of meaon i n t e n s i t y c o l l e c t e d f o r
e l e v e n months a t Gulmfetrg have been ana lysed .
I t i s neces sa ry to c o r r e c t t h e d a t a l o r
m e t e o r o l o g i c a l changes s i n c e meson i n t e n s i t y v a r i a t i o n s
a r e caused fey such f a c t o r s . 2!he e f f e c t of m e t e o r o l i g i c a l
changes h a s heen s t u d i e d by many workers hu t t h e most
i m p o r t a n t c o r r e c t i o n i s r e l a t e d to change i n p r e s s u r e .
I h e i n t e n s i t y a f t e r c o r r e c t i o n may be vvr i t t en ,
I^ssI-^Ap, , fthere I i a u n c o r r e c t e d i n t e n s i t y ,
i s t h e p r e s s u r e c o e f f i c i e n t and p i s t he change i n
p r e s s u r e , f h e v a l u e of ^ could no t be de termined f o r
Gulmarg b e c a u s ^ f t h e absence of r ad iosonde d a t a , but
a va lue of —»• 0 . l 6 ^ per mb. f o r t h i s l a t i t u d e h a s been
g e n e r a l l y accep ted by o t h e r workers and t h e same h a s been
used h e r e , f h e f a c t o r a p may be w r i t t e n as ( p - p ) , where
p i d t h e observed p r e s s u r e and p i s t h e average p r e s s u r e
f o r the month.
S . L I . D o r m a n , Cosn lc - r ay v a r i a t i o n (1957) ,
2 6
5 .02 HA&MOMC AIJALYSIS
She harmonic a n a l y s i s of t h e d a t a h a s been
c a r r i e d ou t t o examine t h e phase and ampl i tude of t h e
f i r s t and second harmonics with t h e h e l p of t h e twelve
b i h o u r l y v a l u e s . These two harmonics a r e a l so termed
" d i u r n a l " and " s e m i - d i u r n a l " waves, and t h e i r "phases"
mean t h e hotxr of t h e maxima of t h e two waves.
3 .03 SggDY WISH THE CUBICAL mESCQPE AT flULMARg
Diurna l v a r i a t i o n of meson c u b i c a l t e l e s c o p e
d a t a c o l l e c t e d a t GulmaTg h a s been s t u d i e d ove r t h e p e r i o d
Pebi*uary, 1958 t o January 1959. The f i r s t and t h e second
harmonic components of meson i n t e n s i t y a f t e r app ly ing
p r e s s u r e c o r r e c t i o n s , a t Gulmsrg^X =24.7°H, 9000 f t . )
f o r d i f f e r e n t months , a r e g iven i n Table 1 . I n appendix
1 , t h e complete d a t a f o r t h e month of November 1958 i s
g i v e n t o g e t h e r wi th t h e d e t a i l s of c o r r e c t i o n f o r p r e s s u r e ,
and of harmonic a n a l y s i s . The changes i n the f i r s t and
the second harmonic components a t taulmarg a re a l s o shown
wi th t h e h e l p of t h e harmoiaic d i a l r e p r e s e n t a t i o n i n
P i g . 10 & 11 . The equipment f u n c t i o n e d e r r a t i c a l l y d u r i n g
A p r i l 1958 due to t r o u b l e with b a t t e r i e s and hence d a t a
f o r t h i s month h a s been exc luded .
Table 1 and F igure 10 show xhat t h e d i u r n a l
ampl i tude and phase of t h e meson i n t e n s i t y do no t e x i b i t
any r e g u l a r v a r i a t i o n over a p e r i o d of 11 months from
27
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o o o o o o o o o o o o ti\0<00tr-ni\>--*t-*tc\tf>t CM H H H r - f H H H r l r-l
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A- FOff THe /yror/THi CO/^Cf/rfteD.
28
Feb* 1958 to J a n . 1959. However, ixi t he ffionths of
March and November, 1958, and J a u u a r j 1959 t h e r e appea r s
t o be a s i g n i f i c a n t change i n the amiplttude. QJhe
ampl i tudes of the d iu i 'na l component i n t h e months of
March, November and Janujary a re 0.545" and 0.52Jb
r e s p e c t i v e l y . Al l t h e s e v a l u e s f a l l i n w i n t e r . For
the^rest of t he months t h e aiapliludeti of t h e d i u r n a l
component a re aimoot c o n s t a n t ( ave rage va lue ^ 0 . 2 4 ^ ) .
The phase of the d i u r n a l component, i n the l a s t two
months (Nov. and Dec. 1958) i s markedly d i f f e r e n t from
t h a t i n t h e r e s t of t h e y e a r ,
The ampl i tudes and p h a s e s , of t h e a e m i - d i u r n a l
component a l s o do no t show any r e g u l a r v a r i a t i o n over
t h e p e r i o d of 11 months s t u d i e d . Here a g a i n the ampl i tude
and phase show a f a i r cons tancy th roughou t t h e s e months,
except f o r the phase d u r i n g March and December 19^-8,
The a p p r e c i a b l e change i n the ampl i tude and
phase of the d i u r n a l component of meson i n t e n s i t y observed
i n w in t e r months may be due to the seasona l change i n
a i r t empe ra tu r e a t v a r i o u s i s o b a r i c l e v e l s .
3 .04 SItJPY VilTH gELBSGOPgS OF DIFFERENT APBRTURE3 AT GULMARG i-
The l a r g e ampl i tudes of t h e s o l a r d i u r n a l
•f These f a c t s have been r e p o r t e d i n t h e a u t h o r ' s paper " J o u r n a l v a r i a t i o n of cosmic- ray i n t e n s i t y a t Gulmarg", P r o c . N a t i o n a l , Aced. S c i . , I n d i a , J i , , Sec, A, P a r t I , 53 (1964) .
29
v a r i a t i o n of mesoa i a t a n s i t y observed i n na r row-ang le
t e l e s c o p e s by t h e Japanese group and o t h e r workers^
encouraged u s t o per form t h i s t ype of s tudy a t t h e
middle l a t i t u d e s t a t i o n , Gulmarg, wi th d i f f e r e n t
narrow angle t e l e s c o p e s . I h u s , a t Gulmarg d u r i n g
t h e y e a r 1958 d i u r n a l v a r i a t i o n of meson i n t e n s i t y
was s t u d i e d u s i n g i n a d d i t i o n to t h e c i b u c a l meson
t e l e s c o p e t h r e e narrow angle t e l e s c o p e s h a v i n g
s emi -ang le s of 4 ° , 7° and 14.5® i n t h e H-S p l a n e and
a semi-angle of 45® f o r each i n t h e £-W p l a n e . The
d a t a a r e c o r r e c t e d f o r ba rome t r i c p r e s s u r e f o r each
month acco rd ing t o t h e method d i s c u s s e d i n s e c t i o n 3 . 1 .
For each day t h e d a t a were smoothed by takcing t h e
moving ave rages over t h r e e c o n s e c u t i v e b i h o u r l y v a l u e s ,
t heave rage v a l u e be ing t h u s c e n t e r e d a t t h e midd le h o u r .
By t h i s method e r r o r s were minimised , f h u s , t h e j f i n a l
v a l u e s a r e o b t a i n e d by adding t h e s e smoothed v a l u e s
f o r the same b i h o u r l y i n t e r v a l s f o r a l l t h e days from
Feb. t o Pec . 1958. P e r c e n t a g e d e v i a t i o n s from t h e mean
a r e p l o t t e d i n F i g . 12 , and t h e cu rves o b t a i n e d a r e
f a i r l y smooth.
She v a r i a t i o n of t h e ampl i tude £uid t h e phase
measured wi th d i f f e r e n t na r row-ang le t e l e s c o p e s i s
g i v e n i n Table 2 . The ampl i tude and t h e phase oT t h e s e
Ti V.Sarabhai and Nerurlcar, Ann. Rev. Nuclear Sc i , 6 , 1 , ( 1 9 5 6 ) .
CM I
a?
i
30
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31
components a re a l s o r e p r e s e n t e d on t h e harmonic d i a l
i n F i g . 13 .
A comparison of t h e r e s u l t s g iven i n Table 2
a s observed with d i f f e r e n t t e l e s c o p e s , b r i n g s t h e
f o l l o w i n g f a c t s to l i ^ t t
She ampl i tude o:l^th8 d i u r n a l v a r i a t i o n becomes
l a r g e r a s t h e a p e r t u r e of t h e t e l e s c o p e s becomes s m a l l e r .
However, t h e d i f f e r e n c e between t h e divirnal ampl i tude
f o r t e l e s c o p e s of and 7® i s not very s i g n i f i c a n t .
j|2i She ampl i tude of t h e s e m i - d i u r n a l v a r i a t i o n
f o r t h e 4® t e l e s c o p e i s much l a r g e r t h a n t h a t of t h e
o t h e r t e l e s c o p e s . Apart from t h i s , no g r a d u a l i n c r e a s e
wi th t h e dec r ea se i n a p e r t u r e i s n o t i c e d .
She phase of t h e diurneO. v a r i a t i o n s h i f t s
r e g u l a r l y tov?ards l a t e r h o u r s d u r i n g t h e day a s t h e
a p e r t u r e of t h e t e l e s c o p e i n c r e a s e s .
| 4 j Ifii® phase of t h e s e m i - d i u r n a l v a r i a t i o n a l s o
i n c r e a s e s wi th t h e a p e r t u r e of the t e l e s c o p e .
5 .05 DAY 20 DAI CHAHGES IM m s DIURHAL VASIATIOH OP CQSMIQ JiAY MESQM IM'X'JjiMsffir
I t i s impor t an t to examine t h e d i s t i n c t i v e
forms of t h e d a i l y v a r i a t i o n t h a t occur on i n d i v i d u a l
days i n o r d e r t o g ive a p h y s i c a l i n t e r p r e t a t i o n of t h e
M£SO/v /NTifi/S/r/
"X
Mtio/^ *
r/c Of^t. s sMOh/fAfc rf,-e f/^s r ^ secc/vc f- ^^AfoA^/e s
c<.itftecr£0 /i^rsoff t/^rfA/j/rv o^
32
s o l a r a n i s o t r o p y of c o s m i c - r a y s . O f t e n , however, t h e
s t a n d a r d e r r o r of expe r imen ta l d e t e r m i n a t i o n i s too
l a r g e t o pe rmi t v a l i d c o n c l u s i o n s aboat i n d i v i d u a l
days , and d a t a a r e t h e n averaged over a number of
d ^ s grouped t o g e t h e r on some c r i t e r i a , f h u s , t he day
t o day changes of t h e a n i s o t r o p y a t Gulmarg were s t u d i e d
u s i n g t h e method sugges ted by S i t t k u s ( 1 9 5 5 ) , ^ ° and
by Eemy and S i t t k u s ( 1 9 5 5 ) . ^ ^ With t h i s method, we have
made a phenomenological c l a s s i f i c a t i o n of t h r e e t y p e s
of d a i l y v a r i a t i o n observed i n meson i n t e n s i t y .
( i ) The *D* t y p e , h a v i n g mexima i n day t ime
between 0800 and 2000 h r s j ( i i ) t h e t y p e , h a v i n g
maxima a t n i g h t between 2000 and 0800 h r s . , and ( i i i )
t h e *HJ)* t y p e , h a v i n g two maxima i n a day.
•HD* type days f o r t h e 1 4 . 5 ° t e l e s c o p e have
n o t been cons ide red because the number of days of t h i s
type were very smal l and hence t h e s t a n d a r d e r r o r i s
l a r g e . She ampl i tude and phase of t h e d i u r n a l v a r i a t i o n
of meson i n t e n s i t y f o r d i f f e r e n t type of days f o r t h e
v a r i o u s t e l e s c o p e s a re g iven i n Table 3 . The c u r v e s drawn
i n P i g . 14 , show s o p e r a t e l y t h e d a i l y v a r i a t i o n f o r
d i f f e r e n t t e l e s c o p e s f o r a l l t y p e s of days .
10^ A . S i t t k u s , J .Atmos. T e r r . Phys . 1 , 8 0 , U 9 5 5 ) . 11 . B.fiemy, and A . S i t t k u s , Z . H a t u r f o r s c h , ^Qa, 172, (1955)
F/G D/9/1 OF MtSO/V frfr£A/S/TY fi-Off D W '/V^' TYPe" D^VS rO/7 . 7'. ft! -^^o *s' T£/.£SCO/>£S
33
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0)
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o vo H
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34
f h e r e s u l t s g iven i n f a b l e 3 sliow tiiat tiie
magni tude o f t h e s o l a r a n i s o t r o p y of pr imary cosmic
r e y s i s l a r g e r f o r t h e •!)« t ype d a i l y v a r i a t i o n thavi
i t i s f o r t h e and «N2>« t y p e s f o r a l l t h e t h r e e
na r row-ang l e t e l e s c o p e s f whi le t h i s i s no t so marked
i n t h e ca se of t h e c i tb ica l t e l e s c o p e . I t i s a l s o
e v i d e n t f rom f a h l e 3 l ^ a t t h e magni tude of a l l t h e
t h r e e t y p e s of v a r i a t i o n s becomes l a r g e r a s t h e a p e r t u r e
of t h e t e l e s c o p e becomes s m a l l e r . (Thus, t e l e s c o p e s of
a a a l l e r a p e r t t i r e a r e more s u i t a b l e t o s t u d ^ t h e v a r i a b l e
c h a r a c t e r of t h e s o l a r a n i s o t r o p y and i t s day tod£^
change, I h e d i f f e r e n c e of phase i n c r e a s e s a s the
a p e r t u r e i n c r e a s e s . I n t he case of t h e t e l e s c o p e ,
t he p e r c e n t a g e of occurence of *DS and »IID*
type of days i s 4 8 . 2 , 27*3» and 24 .3 r e s p e c t i v e l y .
I h i s shows t h a t the S type d a i l y v a r i a t i o n i s more
f r e q u e n t a t Gulmarg t h a n t h e o t h e r t y p e s . •
F i g . 15 shows t h e B a r t e l s diagram f o r 'H*
and 'HD* type of d a y s . Days f o r vihich t he d a t a i s
e i t h e r z ^ t a v a i l a b l e o r i s i ncomple t e a r e a l so
i n d i c a t e d on t h e diagram. I t m ^ be seen f rom t h e
• I n t h e case of n e u t r o n i n t e n s i t y a t Grulmarg Ch.\r .SaBtry ( I960) P h . D . f h e s i s A.M.U.Aligarh found t h a t t h e •!)• type d a i l y v a r i a t i o n i s more f requent j l f .
g Q D Q X
F I C .5
^ 'D' type Dtt'fS 0 '-v' TfPC D/v S
Wd TyPE OA /s „ ///COMPLETe D/i rs
/ i f l f f T E L S D t t ^ C A l / t / ^ r o K ' M D ' T Y P C D / f V S F0/fi'r£Lesc0P£
60
diagrKn t h a t t h e r e i s a tendency f o r D, H aad. ND,
t y p e s of days t o occur i n groups o f and t h i a i s more
prominent i n t h e case of *D* and 'S* type of days . I t
i s a l s o p o s s i b l e to c a l c u l a t e from P i g . 15, t h a t t h e r e
i s a tendency of 27-day r e c u r r e n c e of 'D* and 'H* type of
days .
3 .06 SEPEHDEHC^ pp j h e DIURHAL •AMJ'LITUDB ASP fflASB OH MAGHESPIC CHA&AglEE FIGURE C^.
Maiyr a u t h o r s have examined t h e changes i n
t h e d i u r n a l component a s s o c i a t e d wi th geomagnetic
d i s t u r b a n c e s . From e a r l i e r s t u d i e s , i t i s c l e a r t h a t
t h i s r e l a t i o n s h i p i s r a t h e r c o m p l i c a t e d . Th i s r e l a t i o n -
sh ip h a s been i n v e s t i g a t e d f o r t h e o b s e r v a t i o n s made
a t Gxilmarg, and t h e v a r i a t i o n i n t h i s r e l a t i o n s h i p wi th
l a t i t u d e h a s been examined by a n a l y s i n g the d a t a f o r
Ottawa ( X -57°H)» and C h u r c h i l l ( X * 70®®) • *
The r e s u l t s of t h i s a n a l y s i s have been shown
i n Table 4 , where t h e range of C^ v a l u e s h a s been d i v i d e d
i n t o t h r e e groups a s f o l l o w s t
ho% Q^ 4 0*5, average 0 , 2 0 .
medium 0 . 3 and ^ 0 . 7 , average 0 . 5 6 .
h igh C^ '^ 0 . 7 average 1 . 1 4 .
•These d a t a p e r t a C i n to t h e same p e r i o d a s t h e Gulmarg o b s e r v a t i o n s and they were o b t a i n e d wi th t h e ^ ind p e r m i s s i o n of S r . D.C.Sose.
38
According to Table 4 t h e ^ p l l t u d e of the
d i u r n a l v a r i a t i o n does not show acy s y s t e m a t i c
r e l a t i o n s h i p wi th C^ v a l u e s . However, t h e ampl i tude
of t h e d i u r n a l components f o r a l l s t a t i o n s are
g r e a t e r dur ing t h e days of low C^ t h a n dur ing t h e
days of h i ^ C^. and t h e phase of a l l s t a t i o n s i s
^ m o s t t h e same on days of low and h i ^ C^,
The above ment ioned o b s e r v a t i o n s are i n 12
disagreement wi th the r e s u l t s of Sandstrom (1955)
f o r t h e p e r i o d 1947-50, based on a s t u ^ of t h e meson
component a t Uppsale ( )v » which i s a h i ^
l a t i t u d e s t a t i o n and compares wi th Ottawa ( »57°N).
The r e s u l t s a r e , however, i n agreement with t h o s e f o r
Kodai^Canal ( X - 0 .6°S) a s r e p o r t e d by ( i ) Sarabha i and
Sas t ry (1956)^^ vd.th meson t e l e s c o p e , ( i i ) Sarabhai and
Sa tya p rakash (1960)^^ wi th n e u t r o n moni tor f o r t h e
p e r i o d 1956-57.
Table 4 and t h e g r s ^ h i c a l r e p r e s e n t a t i o n of
t h e d a t a g iven i n F i g . 16, i n d i c a t e t h a t t h e r e are two
12 . A.B. Sandstrom, T e l l u s , J, 204, ( 1 9 4 4 ) . 15 . Y. Sa rabha i , and T.S.G. S a s t r y , Under p r e p a r a t i o n . 14 . T . S a r a b h a i , and Satya Prak:ash, proft-Ind,- , -la/LM
Acad. S c i .
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ft o o o o •H +1 +1 +1 <a H CTi CM o
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38
d i s t i n c t t y p e s o f v a r i a t i o n of the d i u r n a l component
wi th magne t i c c h a r a c t e r f i g u r e * I n t h e case of
C h u r c h i l l and Ot tawa ( X «57®N), t h e v a r i a t i o n wi th C P
i s convex upwards, i ^ e r e a s i n t h e case of Gulmarg
i t i s concave upwards. !Ehe ampl i tude i s no t found t o
i n c r e a s e s y s t e m a t i o a l l y o r m o n o t o n i c a l l y wi th i n c r e a s e
i n Gp, a s found by Sekido and Kodama (1952)^^ f o r
Tokyo ( X = 25 N) whose d a t a can be d i r e c t l y compared
v/ith GtOaarg ( X * 24 .7°N) . I n t h e case of a l l t h r e e
s t a t i o n s t h e ampl i tude i s h e a t e r d u r i n g t h e days of low
Cp t h a n , i t i s d u r i n g the days of higj i C^. The phase
i s found t o remain c o n s t a n t f o r each s t a t i o n from
days of Low C^ t o t hose of h igh C^. on ly i n t h e case
of Gulmarg t h e r e i s an appa ren t anamoly s i n c e t h e
phase i n c r e a s e s very c o n s i d e r a b l y from days of low C^
t o t h o s e of medium C^, and i t resumes i t s low va lue on
days of h igh I t may be no ted t h a t t h e phase
depends on l a t i t u d e ; ^^ i t changes from 224° f o r Gulmarg
t h r o u ^ 192® f o r Ottawa to 155® f o r C h u r c h i l l , Th i s
b e h a v i o a r i s observed f o r a l l t y p e s of days .
15 . I . S i k i d o , and M.Kodama, Hept . I o n o s p h e r e , Res . Japan , 6 , 111, ( 1 ^ 5 2 ) .
I6 . i t .S .Yadav , Ra t . Acad. S c i . I n d i a , Sec. A, 33, 213 P a r t I I I , ( 1 9 6 3 ) .
39
5 .07 m s VOaLD-WIDyS CHANGES IK COStHIQ- AX MESQB MP TUMIR C0&&E1ATI0H WlTli SOLAR
Alijj fe^DMAfeHEi^I^ ACglVli'^T
S ^ s t e a a t i c s t u d i e ^ of tixe l o n g - t e r m changes
i n tile d a l l y v a r i a t i o n of cosmic- ray i n t e n s i t y whicli
a r e world-wide i n c h a r a c t e r kave been r e p o r t e d mos t ly
based on t h e d a t a r e c o r d e d d u r i n g t h e p e r i o d of minimiui
s o l a r a c t i v i t y , Shese a t u d i e e sugges t an a o i s o t r o p y
of the pr imary cosmic r a d i a t i o n xinder s o l a r c o n t r o l .
Here , the|aiBi of the p r e s e n t s tudy i s to use the d a t a
from s e v e r a l s t a t i o n s s i t u a t e d i n d i f f e r e n t l a t i t u d e s ,
and c o l l e c t e d d u r i n g a p e r i o d of maximum s o l a r a c t i v i t y ,
i n o r d e r t o throw f a r t h e r l i g h v on t h e world-wide
c h a r a c t e r of cosmic-ray i n t e n s i t y v a r i a t i o n s , and t o
e x p l a i n t h e r e l a t i o n s h i p between t h e ampl i tude and t h e
phase of t h e d i u r n a l v a r i a t i o n of meson i n t e n s i t y wi th
s imspot numbers and magnet ic c h a r a c t e r f i g u r e C^. I n
t h i s c o n n e c t i o n the monthly changes of the d i u r n a l and
s e m i - d i u r n a l components a t d i f f e r e n t s t a t i o n s d u r i n g
1958, t h e y e a r of maximum s o l a r a c t i v i t y , have been
s t u d i e d , and f a b l e 5 and 6 have been c o n s t r u c t e d .
The s t a t i o n s f o r which d a t a have been c o l l e c t e d
a r e t h e f o l l o w i n g : -
( i ) Makerere ( X » 2 ° S . , R i g i d i t y - 1 4 Bev.)
( i i ) Gulmarg (A «24.7®H., R i g i d i t y =9 .2 Bev.)
to I I w
i-o
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42
( i i i ) Ot tawa Rig ic i i ty « 1 . 7 Bev.)
( i v ) Sulphxir Mountain ( X«58®H, R i g i d i t y = 1 . 1 Bev.)
( • ) C h u r c h i l l ( X =70®H, R i g i d i t y « 0 . 5 Bev.)
( v i ) R e s o l u t e { X «83°H, R i g i d i t y » 0 Bev.)
f h e cu rves i n P i g . 17 r e p r e s e n t t he monthly ampl-
i t u d e of the d i u r n a l component of p r e s s u r e c o r r e c t e d
meson i n t e n s i t y a t s i x s t a t i o n s , t h e monthly mean v a l u e s
of C and t h e sun - spo t numbers f o r the p e r i o d 1958. .It
•The month t o month changes i n the d i u r n a l
ampl i tude f o l l o w a s i m i l a r t r e n d f o r a l l s t a t i o n s
which c o n f i r m s t h e world-wide n a t u r e of the d i u r n a l
component. Bat s t a t i s t i c a l l y s i g n i f i c a n t d i f f e r e n c e s
a re obse rved .
The g e n e r a l n a t u r e of t h e s e cu rves a t Makerere ,
Gulmarg, Sulphur Mountain, C h u r c h i l l and Be s o l u t e
shows a t h e s t a n e g a t i v e c o r r e l a t i o n with s o l a r a c t i v i t y ,
f h e v a r i a t i o n a l s o does not show any d e f i n i t e r e l a t i o n ^ i p
wi th Gp v a l u e s ( P ^ .
Y a r i a t i o n a i n t h e monthly v a l u e s of t h e phase
of the d i u r n a l component of meson i n t e n s i t y a t a l l t h e
s t a t i o n s a r e p r e s e n t e d i n F ig . 18. Comparison of t h e
cu rves f o r Makerere , Gulmarg, Ot tawa, Sulphur Mounta in ,
C h u r d a i l l and R e s o l u t e shows tht i t t h e behaviour i s
rrc / / A/z/VA/ v^/i/u/^ of 7/// f/MPi/rooi 0/ r/ff o//JffA>//7i compo-/V//V7- o r DtfffefA^T ST/7T/OA/S r/PO/*^ y/?/y/or/4fY TO D f C f / ^ B t ^ /9S8
iOV 5 fit, J M/HKKs
riffla - MmrHiy Mfm t^mues or tw tmniroof " or TM o/uMm contPONfNT rtr otrfcueNT sranOA/s fitOM Jnn n Pfc nst
43
q u i t e s i m i l a r excep t a t one o r two p o i n t s .
She behav iour of t h e phase a t Gulmarg i s
remarkahly d i f f e r e n t from t h a t a t o t h e r s t a t i o n s . I n
t h i s case» d u r i n g most of t h e months phase remains
c o n s t a n t .
f h e c o r r e l a t i o n of t h e behavioiir of t he phase
wi th s o l a r a c t i v i t y , and geomagnetic a c t i v i t y shows
the f o l l o w i n g s -
hJi-(1) At Makere^the behaviour i s n e a r l y p o s i t i v e l y
c o r r e l a t e d with geomagnetic a c t i v i t y as we l l
a s wi th o o l a r a c t i v i t y ,
(2) At Gulmarg, i t does no t seem to he c o r r e l a t e d
with geomagnetic a c t i v i t y , but i t shows a
p o s i t i v e l y c o r r e l a t e d behaviour with s o l a r
a c t i v i t y .
(3) At Ottawa t h e behaviour i s n e a r l y p o s i t i v e l y
c o r r e l a t e d wi th geomagnetic a c t i v i t y and a l so
wi th s o l a r a c t i v i t y .
(4) At C h u r c h i l l i t i s n e g a t i v e l y c o r r e l a t e d with
geomagnetic a c t i v i t y whi le i t i s p o s i t i v e l y
c o r r e l a t e d wi th s o l a r a c t i v i t y .
(5) At R e s o l u t e i t r e v e a l s a p o s i t i v e c o r r e l a t i o n
wi th geomagnetic a c t i v i t y , a s we l l a s wi th s o l a r
44
a c t i v i t y - but f o r a s h o r t p e r i o d i n t h e
beg inn ing .
From t h i s comparaJ t ive s tudy i t appeal 's
t h a t t h s phase of t h e d i u r n a l component i a p o s i t i v e l y
c o r r e l a t e d wi th s o l a r a c t i v i t y a t a i l l a t i t u d e s ,
( f a b l e 7 , column 2 ) , ishich shovss t h e world-wide
c h a r a c t e r of t h e phase of the d i u r n a l component of
meson i n t e n s i t y .
I t would appear from Sable 7 column 1 ,
t h a t t h e r e i s no c o n s i s t e n t c o r r e l a t i o n between
phase and geomagnetic a c t i v i t y a s i n d i c a t e d by t h e
world-wide i n d e x C^. I t would p e r h a p s be f r u i t f u l
t o see i f t h e c o r r e l a t i o n wi th l o c a l C^ v a l u e s would
be p o s i t i v e .
5 . 0 8 a?E£ AMPLITUDE AHD THE PHASE OF fHE DIURNAL VARIAI'IOH.
The hour of maximum (phse) of t h ^ d i u r n a l
component depends upon t h e d e f l e c t i o n s u f f e r e d Dy t h e
charged p r i m a r i e s from the sun i n t h e geomagnetic
f i e l d , T h e r e f o r e , t h e world-wide n a t u r e of t h e l o n g -
term changes i n phase may be a t t r i b u t e d t o change i n
the energy spec tmai o r i n t h e r a t i o of t he p o s i t i v e
to n e g a t i v e p a r t i c l e s of t h e r a d i a t i o n which p roduces
a n i s o t r o p y .
I I
1 % Bi
O * •H » 4» 0 S> Xt
o cQ
+ » ©
'H
O >» o > •rl-H cS o
r-i <3 ® S ^ O H O O m m xitt
V I o >»
® -H
<S O m a
a • +» >» •H at
p j •H c
•H O + + as
g) H ^ o a ^ H u o a o
<» *
- p
o - P
o
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• • 0 ^ » t a
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rt - p O • iTi CO { 3 - H CM O - P <M CO
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• H •
<D • r-( o « eio m •H HP o « H (d s i
•H & o r4 •P o OJ o OJ +» - a g +» •P 3 •ct OQ
0 5 o o
45
P a r a o a s and f e n t o n a l s o observed, a c o u s i -VJ
s t e n t phase l a g i n l o c a l t ime of 3 to 4 h o u r s a t Hanson
( X =73®S) r e l a t i v e t o Hobar t ( X « 52°S) . They
e x p l a i n e d t h a t t h i s phase l a g i s not due to a t iaospher ic
i n f l u e n c e , b u t t h a t i t i s due to the primary p a r t i c l e
a n i s o t r o p y o u t s i d e t h e e a r t h * s magnet ic f i e l d , and
a l s o due to t h e d i f f e r e n t d e f l e c t i o n s s u f f e r e d by t h e
charged p a r t i c l e s i n a r r i v i n g a t two d i f f e r e n t s t a t i o n s .
Daring the p e r i o d of low sun-apo t a c t i v i t y , 13
Sarabhai and &ane (1953) ooserved a world-wide
r e l a t i o n s h i p between changes i n t h e ampl i tude and
phase of t h e d i u r n a l component of meson i n t e n s i t y
and they found a p o s i t i v e c o r r e l a t i o n between t h e two.
S h i s shows t h a t the i n c r e a s e of ampl i tude i s a s s o c i a t e d
with t h e s h i f t i n g of phase towards l a t e r h o u r s .
We have a l s o examined t h i s type of world-wide
n a t u r e i n t h e changes between phase and ampl i tude of
the d i u r n a l component of meson i n t e n s i t y a t t h e s t a t i o n s
under s tudy d u r i n g t h e p e r i o d of maximoai sun-apot
a c t i v i t y , by c o n s i d e r i n g the monthly mean v a l u e s of
1 7 . K.H. P a r s o n s , and A.G.Fenton, Huovo. Cimento, (Supplemento) , 8 , Se r . 10 , 311, ( 1958 ) .
18 . V .Sa rabha i , and R.P . Kane, Phys . Rev, 204, (1953)? Phys . Eev, 688 (1953) ; and Ha ture , 171 .122(1953) .
t h e phase and t h e ampl i tude .
From I I g . 19» i t i s c l e a r t h a t t h i s
c o r r e l a t i o n i s n e g a t i v e , which a£,ain c o n f i r m s t h e
world-wide c h a r a c t e r of t he d i u r n a l v a r i a t i o n .
3 .09 iiiHiiiE&Y OF gMii DIURHAL YAiilAlEIQH
I n o rde r t o i n v e s t i g a t e t h e dependence of
t h e d i u r n a l v a r i a t i o n 016 mean pr imary p a r t i c l e energy ,
we s e l e c t e d t h e meson i n t e n s i t y d a t a r e c o r d e d a t
Makerere , Ot tawa, Ghi i rch i l l and R e s o l u t e where t h e
c u t - o f f r i g i d i t i e s a re 14 Bev . , 1 . 7 Bev . , 0 . 5 Bev. ,
and 0 Bev. r e s p e c t i v e l y .
The geomagnetic f i e l d p r e v e n t s pr imary cosmic
r a d i a t i o n s of r i g i d i t y 4 14 Bev, f rom r e a c h i n g t h e t o p
of t h e atmosphere near t h e equa to r ( X » 2 ° S ) . Thus
a l o w - l a t i t u a e meson moni tor i s s e n s i t i v e t o p r i m a r i e s
of r i g i d i t y 14 Bev. The geomagnetic cut o f f
d e c r e a s e s with i n c r e a s i n g l a t i t u d e s , u n t i l a t h i ^
l a t i t u d e s (57|[) p a r t i c l e s o f r i g i d i t y 1 . 7 Bev can be
d e t e c t e d by a meson moni tor p laced t h e r e . Thus by
comparing t h e ampl i tude of the d i u r n a l v a r i a t i o n a t
d i f f e r e n t l a t i t u d e s , energy dependence can be examined.
The monthly mean v a l u e s of t h e d i u r n a l
a a p l i t u d e a t d i f f e r e n t l a t i t u d e s were g i v e n i n Table 5
k
t tf r//i riMf'tiniDi '•f\\y / • / " ' » / //•// O/UMM^L coAf/'OA/if^r o^
PfffiSUHf C O A ' t i , ; / > A// i f A' /-V/^-A/i/.' K fft O t f f / i t i M l ST/9T/OA/S
47
The r a t i o 'R ' t a b i i l a t e d i n Table 8 , i e t he
monthly mean va lue f o r a s t a t i o n monthly mean va lue f o r Mekerere
Ow Average v a l u e s of R shown Table 8 , a r e p l o t t e d
A a g a i n s t t h e r i g i d i t y a t d i f f e r e n t l a t i t u d e s i n P i g . 2 0 .
Th i s shows t h a t t h e ampl i tude of t h e d i u r n a l v a r i a t i o n
of meson i n t e n s i t y a s wel l a s the monthly changes i n
t h e d i u r n a l ampl i tude a re energy dependent .
3 .10 SMI-raLURHAL m i A g l O g 03? ISTBSSITY
For t h e s tudy of t h e s e m i - d i u r n a l v a r i a t i o n
of meson i n t e n s i t y a g a i n d a t a o f Makerere* &ulmarg»
Ot tawa, Sulphur Mountain, C h u r c h i l l and R e s o l u t e a r e
u s e d . Monthly mean s e m i - d i u r n a l ampl i tude and phase
a re c a l c u l a t e d . Only t h o s e days i n a month a re used
f o r which a l l t h e 12 b i h o u r l y v a l u e s a re a v a i l a b l e .
The ampl i tude and phase of the s e m i - d i u r n a l component
a t d i f f e r e n t l a t i t u d e s i s g iven i n Tab le s 9 & 10 .
From Table 9 , i t i s c l e a r t h a t t h e a m p l i t u d e s
of t h e s e m i - d i u r n a l component a t a l l s t a t i o n s a r e q u i t e
s i g n i f i c a n t ( > 3 <r ) , i n a l l t h e d i f f e r e n t months ,
only a t R e s o l u t e the average va lue ^
i 8
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CM o CM m GO I-I Ift CO m r-l <0 H<M t<%<OvO 0%<X)<N S KNH Or-lf-tCVJCMHOr4HOr4r4
<=1- c^cj la cr>c\i irv 00 vo irvcvi tA\ot<-»'si-iA I I I f • • • • • • • • C Jr HK «tf'<M CM H
0} +» la ® M .. <s> 0 ^ ca . . H -s o ^ • 2 >> a p o -
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49
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tr\ NO \o tfN K\ oi e^ e - j T i o CM o o o o o o o o o o o o o o o o o o o o o o o o o o
H H •H
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00 00 CO oo f (0«^^ -ooo^^t^^cM<Mo • • • • • • • • I o o o o o o o o I I I iH o
cne-- CM o H <0 c y v C M v i j OHHrHHOHCM r4 •
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50
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OKNO HrHf-fr-IO t i l l iH HHH t-i
I CVitT* O O O CVI ITi r-»
CM H CM ^ <0 o o ca t*-<rico • •<• • • • • • • • • • m •«(»• CM to lA ^
® • • <I> ® • • 6) <0 S S ® O O S H > o d 0 ® O o ^
$u to • • 3 psi H 3 ft o -H G
51
0 . 0 4 i 0.02?i i s l e sB t h a n 5 ^ and hence I s no t
s i g n i f i c a n t , a l though i n some a o n t h s i t i s s i g n i f i c a n t .
At Gialmargf t h e seai-ci iuri i ial coiaponent i s
a l s o s t u d i u a by a n a l y s i n g the d a t a ot t h r e e narro\v-
a a ^ e t e l e s c o p e s hav ing semi -ang le of 4°, 7° and 1 4 . 5 °
i n t h e K-S p l a n e and the r e s u l t s a r e g iven i n I 'able 2 .
Th is f a b l e shov/s t h a t f o r the 4° t e l e s c o p e t h e a e a i -
d i u r n a l componeni; i s %uite s i g n i f i c a n t and i t i s l a r g e
aa compared t o t h e 7° and 14.!?'^ t e l e s c o p e s . Ihe phase
isa of t h e s e m i - d i u r n a l component i n c r e a s e s with t h e
a p e r t u r e of t h e t e l e s c o p e .
3 . 1 1 THE RELATIOUSBIS 3ETWEEH SEfeai-DIPfiUM. YARIATIOS AND SEOMAGH^nC lESTURBAIiCES.
Table 11 g i v e s t h e ampl i tude and phase of
the semi -d i i i rna l component of meson i n t e n s i t y f o r t h r e e
v a l u e s of C - i . e . low medium ( 0 . 5 < 0 < 0 . 7 ) P P P and h i ^ ( C ^ ^ O . ? ) .
S h i s t a b l e shows t h a t on aays of low, medium
and h i g h C^, t h e ampl i tude of t h e s e m i - d i u r n a l v a r i a -
t i o n i s cdmost t h e same ( a c c o r d i n g t o 3 < r l e v e l ) a t a l l
t h e l a t i t u d e s from 24.7°H to 83°H. But , t he phase of
t h i s component i s e a r l i e r on days of h i ^ Qp a t a l l
l a t i t u d e s abo/e 24.7®N. At 2 4 . 7 ° 5 (Gulmarg) t h e phase
of the s e m i - d i u r n a l v a r i a t i o n i s t he same on days of
52
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p) • •«•» O "Ct « to to ® 4» o a -H •B<N cd a.o H
K5-M O d jS^ ® CO ® •H M >4 <N
jffl
) a
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t ssi
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r4 O
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09
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53
medium and low U^, whi le i t i s e a r l i e r on days of Mgn. C by about one noi i r . IheBe r e s u l t s i j ad i ca t e
P t h a t r a p i d v a r i t t t i o n s i n t h e d i u r n a l component produce
v a r i a t i o n a of seiai- .diurnal componejit wi th r e s p e c t to
C . 2 h i s was sugges ted by Sarabna i and Sa tva Prtikaah P (1960)^^ , Table 11 a l so shows t h a t the ampl i tude and
phase of t h e sen i -d ix jxna l v a r i a t i o n does not show any
s y s t e m a t i c r e l u t i o n s i i i p with G^ v a l u e s a t any l a t i t u d e s .
3 .12 MOHm TO MOSm CHASGBS IK THE AMPLITUDE Abfl3 PHA3£ Of TEE S£MI~DIU&MAL OOMPOWENT AHS gHBlR &£LATI0N ^ITM 0 , VALUES AWFSIJH-SPOT mJMB£RS. F
The monthly mean ampl i tudes , geomagnetic
c h a r a c t e r f i g u r e G^, and r e l a t i v e sun- spo t number ?
are p l o t t e d i n P ig . 21. The monthly mean t i n s of
maximoM ( p h a s e ) , C and r e l a t i v e san - spo t nuabero ^ i
a r e shown i n ? i g . 21 . The f i g u r e s f a c i l i a t e a s tudy A
of t h e i n t e r r e l a t i o n of t h e s e f a c t o r s .
I t can be seen from J i g . 21 and Table 9»
t h a t t he ampl i tude i s almost c o n s t a n t d u r i n g a l l t h e
months a t a l l t he l a t i t u d e s examined h e r e . Tn i s
i n d i c a t e s t h a t the s e m i - d i u r n a l ampl i tude i s not of a
v a r i a b l e c h a r a c t e r . From t h e n&ture of t h e cu rves i n
P i g . 21 i t i s c l e a r t h a t t he t r e n d of the d a t a i s
d i f f e r e n t a t d i f f e r e n t s t a t i o n s as r e p o r t e d by Sarabliai
19 . V .Sa rabha i , and Sa tya P r a k a s h . P r o c . I n d i a n Acad. 3 c i , 84 ( I 9 6 0 ) .
o i 02 0/
0
05
01 O!
a
02
0! o
0 2 01
A
Cp
Mlh/fit Rf
OOL f>f/iKG
RlSOl Off
O N ) r M i\ M J ) M O A f T f i - ^
2r- I^TOf^fTMY O/^ rw /y/H^^/TOOf Of THf Sf*^/- D/uarJ^L Con^A'OA'/rA/T of THi D»aY ^/f?f^J/9T/o/\/ or m£so/y i/i/TfNSiry AT OI/^fi'f^f^T STfTIOf^S.
e t . a l ( 1 9 5 5 ) ^ and Venkatesan and Da t tne r (1959)^^ .
iprom t h e cu rves shown i n F i g . 21» i t I s a l so
c l e a r t h a t the changes i n the ampl i tude of t h e semi-
d i u r n a l component a t a l l the l a t i t u d e s from 2®S t o
83°fi revesil no d e f i n i t e type (t- ve , o r - v e . ) of
c o r r e l a t i o n with s o l a r a c t i v i t y and geomagnetic
a c t i v i t y .
F i g . 22 ^ o w s t h a t t h e r e i s no s i m i l a r i t y
between the s t a t i o n s i n t h e changes i n phase of t h e
s e m i - d i u r n a l compoiaent of meson i n t e n s i t y .
Again t h e r e s u l t s a r e i n agreement witl i t h o s e 21
of V e n k a t e s ^ and Da t tne r (1959) and S a r a b h a i , Desai
and Venkatesan (1955)^^ .
f h e changes i n the phase of the s o m i - d i u r n a l
component do not show any r e l a t i o n %vith geomagnetic
a n d ^ l a r a c t i v i t y , t h e r e f o r e , they could no t be
d i r e c t l y caused by g e o m a ^ e t i c ^ d s o l a r a c t i v i t y .
One nay ssy ' t h a t t h e r e i s no ^^rid-wLde
agreaaenfc i n t h e case of t h e ampl i tude and phase of t h e
s e m i - d i u r n a l component, a s i t was i n t h e case of t h e
d i u r n a l component.
20, V.3arabhai» U.J). Desai* and D.Venkatesan, P h y s . , Eev. 1490(1955) .
21 . B.Venkatesan and A . D a t t n e r , f e l l u s , 21* 1 1 6 , ( 1 9 5 9 ) .
s ^
IT«V Sfv' NvMmies
J J 5 O O
/f U! > ,i,iu or 7M£ Sfftfl OtOfl/^m COMPOAfiMT •/•^TfA/snr /iT otrriMff^ snrto^
5 5
5 , 1 5 ORI&IH OP SOai^DlURSAL VARIATION
The s e m i - d i u r n a l v a r i a t i o n f o r t h e meson
component Ixas boan s t u d i e d p r e v i o t i s l j by E l l i o t ( 1952 ) ,
Be foand s n a i l ampl i tudes ( l e s s t h a n 0.05?^) for EuanCfcgro ( A S) , Godhavn ( A "80 H)t C h r l s t c h u r c h
( X =49®S) fcnd Cheltenham ( X«50®H), Bat o t h e r workers
have foimd q u i t e l a r g e ampl i tudes a t d i f f e r e n t l a t i t u d e s .
Rau (1959)^^ tised two d i f f e r e n ^ i z e d i o n i z a t i o n V
(Members and suspended them i n a v e r t i c a l narrow f i s s u r e
i n a rocky under 40 m e t e r s of water i n l a k e c o n s t a n c e .
Wi'Si t h i s arrangement he obse rved the s e m i - d i u r n e l compo-
nen t with an ampl i tude of 0 . 1 8 + 0.149^*. ' « o l t j e r and 23
Gropoloen (1950) u s i n g s t e l n k e - i o n i s a t i o n a p p a r a t u s
(12 cm. l e a d top s h i e l d , and 10 cm. l e a d s i d e s h i e l d ) ,
found a very s i g n i f i c a n t s e m i - d i u r n a l component with an
ampl i tude of 0.19^» maximum a t 4 h r s . (Local t i m e ) .
£au a s we l l a s W a l t j e r and Gopokoen found
t h a t the s e m i - d i u r n a l component i s n e a r l y I n phase
vCtii t h e s e m i - d i u r n a l component of t h e ba romete r io
p r e s s u r e .
22. W.Saa, Z^fhys . i M , 265 (1959)» 25. fl.a. ifSfoltjer, and Gopokoen, P h y s i c a , 112(1950) .
56
I n I n d i a , a t low l a t i t u d e s Sarabhai e t a l .
(1955) ^ s o otoserved a s i g n i f i c a n t s e m i - d i u r n a l
<^mposent and they found t h a t i t ^ o w s l ong - t e rm (Ganges.
I h e r e s u l t s p r e s e n t e d i n t h i s c h a p t e r a l s o
i^ow t h a t the se f f i i -d iu raa l v a r i a t i o n i s q a i t e s i g n i f i -
can t between the l a t i t u d e s of 2®S and 70°5, but t h a t
a t h i ^ e r l a t i t u d e s i t s v s l u e i s not l a r g e .
Rau (1940)^^ and Ehmert (1940)^^ e x p l a i n e d
laiat t he s i g n i f i c a n t semi-dixirnal component of coamic-
re^ i n t e a a i t y ^ I c h was i n phase with t h e s e m i - d i u r n a l
component of t h e b a r o m e t e r i c p r e s s u r e was due to t h e
a tmospher ic o s c i l l a t i o n s . However, t h e t h e o r e t i c a l
s tudy of S l l i o t and Dolbear (1950, 1951)^^ r e v e a l e d
t h a t s e m i - d i u r n a l v a r i a t i o n i s not due t o a tmospher i c
o s c i l l a t i o n s . Sa r abha i , Desai and Venfeatesan (1955)^®
e x p l a i n e d t h a t the s i g n i f i c a n t s e m i - d i u r n a l component
may not be of a tmospher ic o r i g i n , but t h a t i t h a s a
r e a l e x i s t e n c e .
Venkateean and Da t tne r (1959)^^ s t u d i e d i n
d e t a i l t h e l o n g - t e m changes i n t h e s e m i - d i u r n a l
v a r i a t i o n f o r Huancayo, C h r i s t c h u r c h , and Cheltenham
24. W.Eau, Z.Phys. i i 6 , 105 (1940) . 25. A.Ehmert, S a t u r w i s s , 28, 28 ( 1 9 4 0 ) . 26 . H . E l l i o t , and D.W.H. ^ I b e a r , P r o c . Phya. Soc.
157 (1950) j J .Atmos .Ter t r .Phys . i , 205(1951) .
57
f o r t h e p e r i o d (1959-52) and they found t h a t t h e
changes l a the s emi -d iu rna l ampl i tude were d i f f e r e n t
f o r t h e t h r e e s t a t i o n s . Ihey a l s o found t h a t t h e
t i m e s of maxisia of t h e s e m i - d i u r n a l v a r i a t i o n were
s i g n i f i c a n t l y d i f f e r e n t a t d i f f e r e n t l a t i t u d e s , and
t h e l o n g - t e r m changes i n t imes of maxima were not
c o r r e l a t e d wi th t h e l a t i t u d e s of t h e s t a t i o n s , f h e i r
r e a i l t s a l so show t h a t t h e r e i s no r e l a t i o n between
laie geomagnetic d i s t i a rbances { r e p r e s e n t e d lay G^) and
t h e s e m i - d i u r n a l ampl i tude .
Our r e s u l t s conf i rm t h e f i n d i n g s of yenka te san
and B a t t n e r . One may summarize t h a t s e m i - d i u r n a l
v a r i a t i o n s have been found t o have no c o r r e l a t i o n wi th
geomagnetic and s o l a r ac t iv i fcy and with a tmospher i c
changes . £hey a r e no t even found to have a world-wide
c h a r a c t e r . Under t h e s e c i r c u m s t a n c e s one m ^ e i t h e r
look f o r o t h e r phenomena of a 12 hour p e r i o d with which
s e m i - d i u r n a l v a r i a t i o n may be p h y s i c a l l y r e l a t e d , o r
one may conclude t h a t t h e e x i s t e n c e of t h e Second
harmonic component of "the d a i l y v a r i a t i o n does not
have a p h y s i c a l s i g n i f i c a n c e - i t i s on ly a ma themat ica l
f e a t u r e . Any p e r i o d i c phenomena may be ana lyzed i n t o
i t s ha rmonics , but i t i s n o t nece s sa ry t h a t each harmonic
ms^ have a p h y s i c a l r e a l i t y o r s i g n i f i c a n c e .
5 8
3 . 1 4 D I S C U S S I O N
The d a i l y v a c a t i o n of cosmic- ray i n t e n s i t y
i s g e n e r a l l y d i s c a s s e d i n terma of d i i i r n a l and semi-
d i u r n a l components, or some t i m e s , by t h e d i f f e r e n c e
between the mean i n t e n s i t i e s du r ing the day and n i g h t
h o u r s , i i t h e i t h e r method, the a n a l y s i s i s capab le
of r e v e l i n g on ly t hose changes i n i n t e n s i t y w i t h i n
24 h o u r s \'shich a re g r a d u ^ and r e p r e s e n t d e v i a t i o n s
of i n t e n s i t y ( • ve o r - v e ) , wiiich p e r s i s t f o r
s e v e r a l h o u r s .
I t i s now g e n e r a l l y b e l i e v e d t h a t t h e d a i l y
v a r i a t i o n of xhe cosmic-ray i n t e n s i t y i s due to
a n i s o t r o p y of t h e primary r ^ a d i a t i o n i n c i a e n t on t h e
e a r t h ' s a tmosphere , but i t i s no t c l e a r how t h i s
a n i s o t r o p y i s c r e a t e d . We ana lysed t h e d a t a f o r meson
i n t e n s i t y a t Makerere , Gulmarg, Ot tawa, Sulphur Mountain ,
C h u r c h i l l and Keso lu te and found a s i g n i f i c a n t ^ p l i t u d e
of t h e d i u r n a l component a t a l l t h e l a t i t u d e s from 2°S
t o I f t h e v a r i a t i o n were due to t h e s o l a r magne t i c
f i e l d , we would have got i n s i g n i f i c a n t ampl i t udes a t t h e
e q u a t o r ; on t h e o t h e r hand, i f i t were due to t h e
magnet ic f i e l d of the e a r t h , we would have got i n s i g n i -
f i c a n t a a p l i t u d e s beyond- the • 'knee". T h e r e f o r e t h e s e
r e s u l t s conf i rm t h a t t he d i u r n a l v a r i a t i o n i s due to
59
tlie a i i i so t ropy of t h e primary f l u x . Maliafora (1949)^
and E l l i o t and Boibear (1951)^ r e a c h e d the same c o n c l u s i o n
v^en they s t u d i e d the d i u r n a l v a r i a t i o n witix d i r e c t i o n a l
t e l e s c o p e s p o i n t i n g i n two d i f f e r e n t d i r e c t i o n s i n c l i n e d
e q u a l l y wilii r e s p e c t to v e r t i c ^ i
Ehmert and S i t t k u s (1951) have r e v e a l e d
the d i f f e r e n c e i n ampl i tude bet^veen t h e d a i l y v a r i a t i o n
s imu l t aneous ly measured by an i o n chamoer of o m n i d i r e c -
t i o n a l s e n s i t i v i t y and by a v e r t i c a l coun te r t e l e s c o p e
h a v i n g a more l i m i t e d d i r e c t i o n a l s e n s i t i v i t y , Sekido
e t , a l . (1950)^®*^^ iiad p o i n t e d ou t t h a t the amp l i t udes
of the f i r s t harmonic component of the d a i l y v a r i a t i o n
of CO smic-ray i n t e n s i t y becomes l a r g e r as t h e a p e r t u r e
of the t e l e s c o p e becomes s m e l l e r . These a u t h o r s based
t h e i r r e s u l t s on a s tudy by two t e l e s c o p e s 12° and 40®.
Our stucly a t Gulmarg dur ing t h e y e a r 1958, u s i n g a
c u b i c a l t e l e s c o p e and t h r e e narrow angle t e l e s c o p e s
hav ing semi-angle of 4®, and 1 4 . 5 ° i n t h e N-S p l a n e
and s ^ i - a n g l e of 45° each i n the E-1 p l ane a l s o showed
t h a t the ampl i tude of t h e f i r s t harmonic component of
t h e d a i l y v a r i a t i o n i n c r e a s e s a s t h e a p e r t u r e of t h e
t e l e s c o p e s i s r educed .
27. A. Ehmert, and S i t t k u s , A, a . H a t u r f o r s c h , ^ , 613(1951) . 28. T. Sekido, M. Kodana and T. Yagi , Hep. Ionosphe re
E e s . J a p a n , 207(1950) . 29. I . S e k i d o and S.Yoshida, Rep . Iono . R e s . J a p a n , 4 , 3 7 , ( 1 9 5 0 )
60
flae change oX ampl i tude with t h e angle of
the t o l e s c o p a s i s shovm i n K g . 25, and i t may-be
n o t i c e d t h a t t h e r a t e of change i n the ampl i tude i s
f a r f rom c o n s t a n t , f o r l a r g e a a ^ e a the r a t e of
change iTi ampl i tude i a very l i t t l e , tout f o r narrow
a n g l e s t h e change i s r s ^ i d . The g e n e r a l t r e n d of
i n c r e a s i n g v a r i a t i o n wi th nar rower a n g l e s of t e l e a c o p e a
i s e x p l a i n a b l e on the b a s i s of an ave rag ing e f f e c t .
However, i t i s s t r a n g e a t t he ave rag ing e f f e c t i s so
n e g l i g i b l e between t e l e s c o p e a n g l e s of about 16^ and
45* o r l a r g e r , a p l a u s i b l e e x p l a l n a t i o n may be t h a t
t h e incoming r a o i a t i o n h a s energy a n i s o t r o p y as we l l
a s d i r e c t i o n a l a n i s o t r o p y and d i r e c t i o n a l a n i s o t r o p y
I s mucbi l a s s s i ^ f i c a n t t h a n energy a n i s o t r o p y .
f h e r e l a t i o n of ampl i tude and phase of t h e
d i u r n a l component with t h e magnet ic c h a r a c t e r f i g u r e Cp
h a s been s t u d i e d by meanB of i o n i z a t i o n c h a a b e r s
and coun te r t e l e s c o p e s by Bhmert and S i t t k u s (1950)^®
Sefcido and Yoshida ( 1 9 5 0 ) ^ and by i a i i o t and Dolbear 2
(1951) • fiowever, ^ e r e i s no g e n e r a l agreement between
t h e r e s u l t s of t h e v a r i o u s a u t h o r s . E i r o r e t a l . ( 1 9 5 4 ) ' ^
h a v ^ ^ o ^ n t h a t the m p l i t u d e of the diarn&L v a r i a t i o n
i n c r e a s e s on ciaye of h i ^ geomagnet ic p l a n e t a r y i n d e x 50 . Sas t r j? , Ch. V. , p h . B . T h e s i s , Al igarh Muslim U n i v e r s i t y ,
A l i g a r h ( I n d i a ) , I 9 6 0 . 31 . J . A . f i r o r , W.H. l o n g e r , and J .A .3 impson ,phys .Kev ,
M . 1051 ( 1 9 5 4 ) .
6
K^ and t h a t t he I n c r e a s e i n ampl i tude i s not caused
by a change i n t h e geomagnetic f i e l d , S i t t k u s (1955)^^
0 n t h e o t h e r hand found t h a t days of i a r g e amp l i t udes
were not always a s s o c i a t e d wi th l a r g e v a l u e s .
Sogg (1949)^^ found t h a t t h e phase of t h e d i u r n a l
V a r i a t i o n was e a r l i e r on m a g n e t i c a l l y d i s t i i r b e d days
t h a n t h a t on q u i e t days , but t h e ampl i tude remains
c o n s t a n t . Ramanathan (1956)^^ a t low l a t i t u d e s
( X «13®5) obse rved t h a t t h e d i u r n a l ampl i tude was
more on days of h i ^ G^ v a l u e s t h a n t h a t on days of
low C v a l u e s . Host of t h e s e r e s u l t a re based on P
t h e d a t a c o l l e c t e d b e f o r e 1954. Owing t o t h e low
c o u n t i n g r a t e of most of t he i n s t r u m e n t s i n u s e a t t h a t
t ime the l i m i t s of e r r o r were c o n s i d e r a b l e . I h u s i t
was wor thwhi le t o perform t h i s s tudy a g a i n i n a more
s y s t e m a t i c w ^ a t d i f f e r e n t l a t i t u d e s wi th i n s t r u m e n t s
o f h i ^ coun t ing r a t e . I h i s o p p o r t u n i t y was p r o v i d e d
by t h e I . G . Y . programme, and t h e d a t a i s , t h e r e f o r e ,
c o n s i d e r e d s t a t i s t i c a l l y more r e l i a b l e .
5 . 15 BXPLAamOS OF mgafiAL YAElAiglQH
She t h e o r y of t h e d i u r n a l v a r i a t i o n of c o a » i c
r ^ s i n te rms of t h e magne t i c f i e l d of t h e sun a s
32. A.E.Hogg, J .Atmos l e r r . Phys . i , , 114 (1950) j J .Atmos T e r r . P h / s . 1, 56(1950) .
33. K.Hamanathan, P r o c . I n d i a n , Acad.Sci .Vol .XLIV,Ho.5 Sec. A, 307 (1956 ) .
62
sugges ted by Janossy (1957)^^ p r e d i c t s t h a t t h e
ampl i tude of t he d i i i rna l component should change
v^th l a t i t u d e , Ees ia l t s of t h e s t a t i o n s we have
ana lysed i n Ch. lY do not show t h e s imple l a t i t u d e
dependence p r e d i c t e d by J a n o s s y . V a l l a r t a and
Godart (1959)^^ and more r e c e n t l y S inger
have shown t h a t t h e r e wo\ild be no s o l a r d i u r n a l e f f e c t
dae to t he magne t ic f i e l d a t the s u r f a c e of t h e sun
f o r p a r t i c l e s of energy g r e a t e r t h a n 9 Bev. Again
we have observed d i u r n a l v a r i a t i o n atA»20s i-®-
f o r p a r t i c l e s of energy g r e a t e r t h a n 14 Bev. P i r r o r 37
et^ a l . (1954) observed the dixirnal v a r i a t i o n f o r
nesatron i n t e n s i t y even a t t h e equa to r i . e . f o r
p a r t i c l e s of energy g r e a t e r t han 15 Bev. Our r e s u l t s
t o g e t h e r 'svith t h e ev idences produced by o t h e r a u t h o r s
show t h a t Janossy* s t heo ry i s u n t e n a b l e , 38
Jfagashima (1955) h a s ejcamined t h e p o s s i o i l i t y
of e x p l a i n i n g a d i u r n a l v a r i a t i o n of the o r d e r of
0 , 2 to 0.53^ on the b a s i s of ah e l e c t r i c f i e l d t h e o r y . i 2 h i s t heo ry a l s o p r e d i c t s ^ ^ g e l a t i t u d e dependence
34 . L . J a n o s s y , Z.Phys. 10^, 430 (1937) , 35. V a l l a r t a , M.S. and G o d ^ , 0 . , Rev. ffiod.Phys.iJ,,
180(1939) . 36. S . F . g i n g e r , P r o g r e s s i n Elementary p a r t i c l e
and Cosmic-ray phys . V 0 I . 4 , 503(1958) . 37 . F i r o r , e t / . a l . , Phys . Eev. 1031(1954) . 38. K.Kagashims, J.Geomag. Geoe lec t . J , 51 (1955)
63
of t h e d i u r n a l v a r i a t i o n which i s not obse rved by u s 39
or by e a r l i e r workers . Ponger (1953) h a s shown
t h a t the d iurnea v a r i a t i o n s i n cosmic- ray i n t e n s i t y
a r e not caused by t h e g e o e l e c t r i c f i e l d .
Burnberg and Da t tne r (1354)^® have shown
t h a t , seen from a f i x e d c o o r d i n a t e system, t h e r o t a t i n g
sun W3uld be s t r o n ^ y p o l a r i s e d , so t h a t t h e r e would
be a p o t e n t i a l d i f f e r e n c e between t h e p o l e s and t h e
s o l a r e q u a t o r of t he o r d e r of 10^ v© I'fcs. The combined
a c t i o n of the e l e c t r i c f i e l d t h u s produced and t h e s o l a r
magne t i c f i e l d v?ill cause t h e charged p a r t i c l e s coa ing
from t h e ga laxy to r o t a t e with t h e sun, so t h a t t h e
e a r t h fldll r e c e i v e more p a r t i c l e s on t h e even ing s i d e
t han on the morning s i d e . I n t h i s way t a n g e n t i a l
a n i s o t r o p y i s supposed t o e x i s t . But our r e s u l t s a s
wel l a s t h o s e of e a r l i e r workers^^ show t h a t t h e t ime
of maximum of l ^ e d i u r n a l v a r i a t i o n occvirs a t noon, JO
or even b e f o r e noon. Al fven (1954) on t h e o t h e r hand ,
h a s shown the p o s s i o i l i t y of an ou t ward r a d i a l f l o w d
of energy depending on t h e a c ^ e r a t i n g p r o c e s s w i t h i n
59. W.H. Ponger , Phys . £ e v . 351 ( 1 9 5 3 ) . 40 . E.A. Burnberg and A .Da t tne r , S e l l u a , J , 7 3 ; 254,(1954) 41 . Nuovo Qlmento, 6 U^S7) " 42. H. A l fven , Phys . Eev. 1082 ( 1 9 5 4 ) .
64
t h e s o l a r system, f h l s «r l l l Impar t a r a d i a l a n i a o t r o p y
to c o a m i c - r a y s , which w i l l be changed wi th 11 -yea r
cyc l e of s o l a r a c t i v i t y . These e x p l a n a t i o n s reqvi i re
a genera l magne t ic f i e l d of t h e sun of t h e o r d e r of
10"^ ganss i n t h e r e g i o n of t h e e a r t h t o account f o r
a diurnaQ. v a r i a t i o n of the o r d e r of 0,2$>,
E e c e n t l y , on t h e b a s i s of t h e i r r e s i i l t s and
o t h e r p u b l i s h e d d a t a , E l l i o t and fiothwell (1956)^^
sugges ted t h a t t h e d i u r n a l v a r i a t i o n may be produced
by the modu la t ion mechanism o p e r a t i n g on pr imary
coanic-rfiQrs w i t h i n t h e r e g i o n of t h e e a r t h s magne t i c
f i e l d . The world-Wide c h a r a c t e r of t h e changes i n t h e
ampl i tude and phase of the divirnal v a r i a t i o n and t h e i r
c l o s e r e l a t i o n with s o l a r a c t i v i t y which we obse rved
suppor t t h i s s u g g e s t i o n ,
The f o l l o w i n g i n t e r e s t i n g f a c t s have emerged
from more r e c e n t d a t a , i n c l u d i n g our own, and a t h e o r y
of d i u r n a l v a r i a t i o n h a s t o e x p l a i n t h e s e f a c t s . The
o l d e r U i e o r i e s were propounded when i n s u f f i c i e n t f a c t s
were known and t h e r e f o r e t h e r e i s need xor c o n s i d e r a t i o n ,
m o d i f i c a t i o n o r r e t h i n k i n g .
45 . H. E l l i o t , and d . E o t h w e l l , PhiL U a g . l , 669(1956) .
65
( i ) f h e jyapl i tude and phase of t h e d i u r n a l
V a r i a t i o n changes from day t o day, and y e a r t o y e a r .
At v a r i o u s o c c a s i o n s and p l a c e s , t h e maximum may
occur a t e i ^ t ime d u r i n g t h e day.
( i i ) There a r e two t y p e s of d i u r n a l v a r i a t i o n s
one wi th maximum d u r i n g t h e day type) and t h e
o t h e r 'sCQi maximum a t n i ^ t , (B t y p e ) .
( i i i ) The *!>* and type of days occur g e n e r a l l y
i n groups of t w or t h r e e days and t l i e r e i s a 27-day
r e c u r r a n c e i n th«a .
( i v ) H e i t h e r *33* nor •H' type d i u r n a l v a r i a t i o n
h a s got any r e l a t i o n wi th geomagnetic a c t i v i t y .
(v) The phase of t h e d i u r n a l and s e m i - d i u r n a l
compomnts i n c r e a s e s wi th t he a p e r t u r e of t e l e s c o p e s .
The phase of t h e y e a r l y mean d i u r n a l component
shows l a t i t u d e dependence.
( v l i ) The phase of t h e d i u r n a l v a r i a t i o n shows a
p o s i t i v e c o r r e l a t i o n with s o l a r a c t i v i t y , wh i l e t h e
ampl i tude shows a n e g a t i v e c o r r e l a t i o n .
( v i i i ) Changes i n phase a r e n e g a t i v e l y c o r r e l a t e d
wi th 'Uie ampl i tude of the d i u r n a l component a t v a r i o u s
l a t i t u d e s .
66
( i x ) I t i s shown by Sekido and Y o ^ i d a (1953)^^
tHat the d i u r n a l ampl i tude i s markedly de te rmined
by t h e d i r e c t i o n e a s e n s i t i v i t y of t h e r e c o r d i n g
i n s t r u m e n t . The change i n ampl i tude wi th t h e semi'-
angle of t h e meson t e l e s c o p e s i s very much more
t h a n normal ly expec ted . Large amp l i t udes o f the o r d e r
of 1 - 2 p e r c e n t have been obse rved by a s as v;ell as by
e a r l i e r mxkera.
The changes i n the ampl i tude with geomagnetic
and s o l a r a c t i v i t y and the f r e q u e n t day to day changes
i n t h e d i u r n a l v a r i a t i o n , obse rved by u s , showing t h e
v a r i a b l e c h a r a c t e r of t h e a n i s o t r o p y make i t n e c e s s a r y
to e v a l u a t e t h e p h y s i c a l meaning to be a t t a c h e d t o
average a n i s o t r o p y .
The d i u r n a l v a r i a t i o n of the 'D*, 'N* and 'ID*
type iKiiich occur i n groups of days and t h e f r e q u e n t
cSianges i n t h e ampl i tude of t h e d i u r n a l component
make i t appear t h a t t h e r e may be a v a r i a b l e a n i s o t r o p y
superimposed on an average or permanent a n i s o t r o p y .
At p r e s e n t i t i s d i f f i c u l t to accep t t h e i d e a of a
permanent a n i s o t r o p y because i t s f e a t u r e s and c h a r a -
c t e r i s t i c s have not been d i s c o v e r e d . I t would appear
Ali^aUl^^ 114 ti'.
67
t h a t i t s f e a t u r e s have been masked by a more prominent
a n i s o t r o p y of a h i g h l y v a r i a b l e c h a r a c t e r .
From p r e s e n t I n d i c a t i o n t h e most f e a s i b l e
t h e o i ^ appea r s t o be one due to E l l i o t and a > l b e a r ( l 9 5 l ) «
Hagashima (1955) aa m o d i f i e d by Herurkar (1957)^^ .
Th i s theory g i v e s a p l a u s i b l e e x p l a n a t i o n of s e v e r a l
s i g n i f i c a n t f e a t u r e s of t h e d a i l y v a r i a t i o n of a e s o n
i n t e n s i t y on the b a s i s of t h e c r e a t i o n of an a n i s o t r o p y
by the p re sence of s o l a r beams of i o n i z e d m a t t e r i n
t h e nei |^)x>urhood of t h e e a r t h . These beams a re
supposed to have t r a p p e d magne t ic f i e l d d e r i v e d from
a c t i v e r e g i o n s on the s u r f a c e of t h e sun . Adopting
t h e d e n s i t y and v e l o c i t y of i o n i z e d m a t t e r i n t h e
beams c o n s i s t e n t with s o l a r geomagnetic d i s t u r b a n c e s i
and assuming a st i-ength of the t r a p p e d magne t i c f i e l d s
compat ib le with e l e c t r o ^ n ^ i c a l c o n s i d e r a t i o n s , i t
i s p o s s i b l e to d e r i v e a d a i l y v a r i a t i o n of meson
i n t e n s i t y which cou ld have a maxLmiam d u r i n g e i t h e r dqy
o r n i j ^ t h o u r s . Th is 'N' and t y p e s o f d a i l y v a r i -
a t i o n would occur i n groups of days which would have
a tendency of 27-day r e c u r r e n c e ( t h e s e f e a t u r e s were
obse rved i n our a n a l y s i s f o r 'D* and type of
d i u r n e i v a r i a t i o n a t Gulmarg). The d a i l y v a r i a t i o n
would have an ampl i tude upto Xi» on i n d i v i d u a l days .
102
The ampl i tude us we l l a s phase of each t y p e of
d a i l y v a r i a t i o n be expec ted to a l t e r dur ing
each group. There would be a p o s s i b i l i t y of d a i l y
v a r i a t i o n wilii two maxima on some o c c a s i o n s ( i . e .
'ND* type d a i l y v a r i a t i o n which was ooserved by
us a t Gulmarg), However, K u r u r k a r ' s t h e o r y does
not ssy a n y t h i n g about permanent a n i s o t r o p y of cosmio-
r ^ a .
CHAPTER IY«
LAi;i!gg]}E Am ALSlirUm OF THE DIURifAL AND SMI^mgiillAX. YAaiATIOM 01* COSMIC
RAJ III!D£HSIgY.
k s tudy of t h e l a t i t u d e dependence of the ampl i tude and piiase of the d i u r n a l v a r i a t i o n of
cosmic- ray i n t e n s i t y i s a very i m p o r t a n t t o o l f o r
u n d e r s t a n d i n g t h e energy spectrum of t h e pr imary
a n i s o t r o p y r e s p o n s i b l e f o r t h e d a i l y v a r i a t i o n .
Donaan (1957)^ h a s c a l c u l a t e d t h e energy spectrum
f o r t h e p e r i o d 1957-51 u s i n g t h e d a t a of meson
i n t e n s i t y r e c o r d e d by i o n i s a t i o n chambers.
There a re a few r a t h e r u n s y s t e m a t i c r e p o r t s
on t h e s tudy of l a t i t u d e dependence of d i u r n a l
v a r i a t i o n . Thompson (1958)^ , u s i n g t h e d a t a of
Gompton and Turner (1937)^ c o l l e c t e d on the P a c i f i c
Ocean between Vancouver and Sydney^ showed t n a t bo th
t h e ampl i tude and phase a r e approximate ly independen t
of l a t i t u a e . Thambyahpi l la i and U l i o t (1953)^ s t u d i e d
1 . L . I . , Dorman, Coamic-r^jr v a r i a t i o n ^ P u b l i s h e d by S t a t e P u b l i s h i n g House f o r Techn ica l and T h e o r e t i c a l l i t e r a t i i r e , Moscow, ( 1 9 5 7 ) .
2 . J . L . Thompson, Phys .Hev . , 95 ( 1 9 5 8 ) . 3 . A.ti. Compton, and Turne r . Pl ys. R v. <51 Whi) 4 . Thambyahpi l la i and H . E l l i o t , H a t u r e r H i , 918(1953) .
? 0
t h e d i u r n a l v a r i a t i o n , bu t they found no s i g n i f i c a n t
dependence on l a t i t u d e . F i r o r e t a l . (1954)^ ,
however, have found an i n c r e a s e i n ampl i tude v?ith
l a t i t u d e . Th i s c o n c l u s i o n i s based on t h e a n a l y s i s
of two s t a t i o n s v i z . Climax ( X » 48°H) and
Huancayo ( X » 0® ) and they found a r a t i o of.
the o r d e r of 1 . 4 + 0 . 0 2 i n t h e peak to peait v a r i a t i o n
between t h e two s t a t i o n s .
f h e a n a l y s i s of t h e d a t a of fluancs^yo (X«0® )
Cheltenham ( X t.SO^S), G h r i s t c h u r c h ( 48®S) and
Godhavn ( X » SO^N) where t h e h a r d component d a t a h a s
been averaged over e i ^ t - y e a r s , b r i n g s t o l i g h t t h e
f o l l o w i n g f a c t s » -
(1) IThat t h e v a r i a t i o n a t Cheltenham and
Chr ia t ch i i r cn , wnich a re symmet r ica l ly s i t u a t e d
with r e s p e c t to t h e ecjuator , a r e s i m i l a r and t h e
hour of maximum i s a l s o approximate ly t h e same.
(2) I h a t t h e ampl i tude of v a r i a t i o n a t Godhavn
( X »80 N) which i s s i t u a t e d near t h e p o l e i s s m a l l e r
t h a n a t t h e o t h e r t h r e e s t a t i o n s and
5 . J . A . F i r o r , W.H.Fonger, J . A . and Simpson, Phys, Jiev. 1051 (1954) ,
71
(5) t h a t t h e d i i i rna l v a r i a t i o n s a r e a p p a r e n t l y
of i r r e g u l a r c h a r a c t e r .
These da t a were of a h igh degree of accu racy ,
l e t i t i s d i f f i c u l t to draw dependable c o n c l u s i o n s
from them, because t h e s tudy i s not very s y s t e m a t i c
between t h e r e g i o n from equa to r t o p o l e i n bo th t h e
hemi - sphe re s of t h e e a r t h . Thus, i t was thought wor th -
whi le to e x t e n s i v e l y s tudy the l a t i t u d e dependence of
t h e diiurnal and s e m i - d i u r n a l v a r i a t i o n of bo th a e s o n i c
and n u c l e o n i c components of t h e cosmic- ray i n t e n s i t y .
Data c o l l e c t e d du r ing t h e I . G . I . ( J a n . t o Aug.
1958) h a s been used by u s f o r a n a l y s i n g t h e l a t i t u d e
and a l t i t u d e e f f e c t s of c o s m i c - r a y s . *e have a n ^ y z e d
t h e r e s u l t s of o b s e r v a t i o n s t a k e n a t the s t a t i o n s
shown i n Table 12 .
The s tudy has been d iv ided i n t o two p a r t s •
( i ) t he d a t a of t h e s t a t i o n s have been averaged
f o r a l l t h e a v a i l a b l e days over t h e e n t i r e
1 . 5 . x . p e r i o d . T h i s averaged d a t a have been
h a r m o n i c a l l y ana lyzed . The r e s u l t s , i . e . ,
the ampl i tude and phase of t h e f i r s t and second
harmonic components a re g iven i n Tab le s and
14.
72
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73
( i i ) The d a t a f o r m a g n e t i c a l l y d i s t i i rbed and qi i ie t
da^s o n l y , f o r t h e p e r i o d , have been
averaged and a n a l y s e d - s e p a r a t e l y . Th i s
s e l e c t i o n has been done to compare the
l a t i t u d e dependence on u n d i s t u r b e d days wi th
t h a t on d i s t u r b e d days .
4 . 1 LATITUDE DBfEHDJEBCE OF !CJA£ AMfLItTUl E Qg THJB JIURHAL AUD S£MI~3)IU&HAL VABIMION.
I t i s apparen t from Tab les 15 and 14 t h a t t h e
ampl i tude of t h e d i u r n a l component of meson as we l l
as n e u t r o n i n t e n s i t y does not show i n c r e a s e o r
dec rease mono ton ica l ly with l a t i t u d e . However, f o r
s t a t i o n s s i t u a t e d nea r t h e p o l e , t h e ampl i tude i s
a p p r e c i a b l y s m a l l e r t h a n a t o t h e r p l a c e s . These
r e s u l t s a r e I n agreement with t h o s e of Iielchvir (1961)^
viio found i t i n t h e case of n e u t r o n i n t e n s i t y o n l y .
The ampl i tude of t h e s e m i - d i u r n a l component
a l s o does not show any l i n e a r v a r i a t i o n wi th l a t i t u d e .
A very s i g n i f i c a n t o b s e r v a t i o n , however , i s
t h a t i n t h e case of meson i n t e n s i t y i n t h e n o r t h e r n
hemisphere , the ampl i tude of bo th t h e d i u r n a l and
6 . Lekhvi r Sud, Ph.D. T h e s i s , Pu^ao U n i v e r s i t y , Chandigarh (pb) I n d i a .
7 4
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76
seml-<ituriial v a r i a t i o n a t f i r a t i a c r e a s e s wi th
l a t i t u d e ! ^ |}ut t h e t r e n d i s r e v e r s e d a t about a
l a t i t u d e of 57°S. 2iie r e a s o n f o r t h i s s t r a n g e
behav iour of meson i n t e n s i t y h a s y e t to be found ,
4 . 2 LAgL^OOB BSPBSDBHCE Q? £SASB Of gHJS PlPaSAL AlfP SMI-mgHHAL YARlAflOS^
But f o r (Julmarg (2700 m e t e r s ) and Makerere
(1196 M e t e r s ) , a l l s t a t i o n s o f Sab le 12 a r e s i t u a t e d 7
n e a r l y a t sea l e v e l - Sarahha i e t a l . (1955) have
shown t h a t t h e phase of t h e d i i i r n a l component of meaon
i n t e n s i t y dec reased w l ^ a l t i t u d e , keep ing l a t i t u d e
c o n s t a n t . Our r e s u l t s bea r t h i s o u t f o r meaon a s
w e l l a s n e u t r o n i n t e n s i t y , f h i s means t h a t t h e phase
f o r t h e s t a t i o n s tidiich would be s i t u a t e d a t t h e same
l a t i t u d e a s Oizlmarg and Malcerere but a t s e a l e v e l
would be someidxat l a t e r t h a n «ha t h a s been s^own i n
S a b l e s 15 and 16. Hence ou r conc lu s ions r e g a r d i n g
t h e l a t i t u d e dependence of phase , w i l l no t be a f f e c t e d
by t h e a l t i t u d e s of Gulmarg and ilak^erere.
f rom f a b l e s 15 and 16 and f i g u r e s 25 and 26, i t
a p p e a r s t h a t t h e phase of t h e d i u r n a l component of
meson i n t e n s i t y a s we l l as t h a t of n e u t r o n i n t e n s i t y
d e c r e a s e s a s l a t i t u d e i n c r e a s e s i n the n o r t h e r n
7 . Y. S a r a b h a i , U.D. Desai and D.Vehkatesan, P h y s . , E e v . , 1940 ( 1 9 5 5 ) .
?7
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?9
l iemisphere . One does no t f i n d t M a r e s i a t i n t h e
s o u t h e r n hemisphere .
I t i s 3eea from Table 1? and 18 aud Fit^. 2?
and 28 t h a t t h e t r e n d of l a t i t u d a dependence of t h e
phase of t h e d i u r n a l component of meaonaa wel l n e u t r o n
i n t e n s i t y i s no t e f f e c t e d by magnet ic a c t i v i t y i n t h e
n o r t h e r n hemisphere .
I n the ease of s e m i - d i u r n a l v a r i a t i o n tne phase
of meson as we l l a s n e u t r o n i n t e n s i t y does not show any
s y s t e m a t i c v a r i a t i o n ( d e c r e a s e o r i n c r e a s e ) wi th
l a t i t u d e i n ho th the h e m i - s p h e r e s . But on m a g n e t i c a l l y
q u i e t days the phase f o r both meson and n e u t r o n
i n t e n s i t i e s d e c r e a s e s wi th l a t i t u d e i n t h e n o r t h e r n
hemisphere only(P^^^'^)
4 . 3 ^ T I T U M DEFBtlDgSOB OF THE PHASE
To exaiaiE^ t h e a l t i t u d e dependence of t h e
phase of t h e d i u r n a l and s e m i - d i u r n a l components of
cosmic-ray i n t e n s i t y , we ana lysed t h e d a t a of t hose
s t a t i o n s livhich a re s i t u a t e d n e a r l y a t t h e same, l a t i t u d e
b u t a t d i f f e r e n t i a l t i t u d e s . Among t h e I . G . Y . s t a t i o n s ,
we s e l e c t e d s i x which s a t i s f y t h e above c o n d i t i o n s .
I n t h i s l i s t , 5 groups of two s t a t i o n s f o r a p a r t i c u l a r
. Diififrbec/ Da^s 0vtet Dt^s
2o/t K
U 0 57N T^/v (fsV
fij-.Zl L ^ T/raos —^
L^T/TL'DF DFPff^OBr\/C£ OF THF PN/9SF fij-.Zl O^T^F D/URr\//Jl COAfPO/^F^T CJF MFSOA/ INTFNSI7Y /V T^F A^OfiTHEfiN HFM/SP/^F^£.
r-iH I i
(0
• 2
Q a O O O o t r v o o i e \ o « f i K N o v o <D \ o H (T \ O o • • • • • • • •
O t t - CO O VX> O CM t r v 9 n H
Q ^ 4 3 S rt
o O
O - H KX O t<^ c - KN KN y x o t - KN 0 0 CM i l - CM v o
® o • • • • • • • • o H O o r - l f -4
05 H +> ea H H
II • p • O t - t - i r \ ON O o o « rt a> ta • • • • * • • •
^ « < 5 - 0
o O CM CFS t A H v o J H rt V l o < 5 - 0
H t-4 H i H H r H
<» a XS o ^
o (S o
V I o •c i
o o H 0 0 t - KV • • • • • • • •
es 5 •¥» OS 0 0 CM K \ CM CM t<^ s i a II
0 0 H CM CM CM
P i A II • •
• n » » 0 3 CO Oi CO 05
X
O o O O o O o O ea +»
X tr\ o CM t o H
a-H X 0 0 t- lf\ H K\ t-9 aS
O H
• •
H • • •
O) ® H a> n -H fi +» •H • ^ H •
o <0 d a •H iH •o » U o n o OS <o « o » CJ ra o »
<& XI a) 0 Q} a CO o o a t£S XI
8 i Q - q d s f o r e H Q i e n d e T i n s H njaq^nog
118
»
1 O
e> d> 0 0 lO
o 5 KN tn KS CO o o K> ti •H > • • • • • • •
CO CO o o H l^-ri 04» o d d O o o OH o d P) o tJ s-e M o. (D O o S o JQ O 0) o S o e- r- o s
O <0 o CJ « s iH ITV m o o 01 •p a # • • • • • m tti a o a t> o o o l<\ r-J K\ 1-1 tti
ra+a o aJ •a •
m o o r- V0 O (A <Tt g o a; • • • • • • » H ^ > CO CO t-4 cn U\ to lA OtJ 51 CJ c CO r4 H i-t T-« <i> xf eye
0 -H CO •
i a d SQ 3 o* -H O Vi ^ +» tJ a a ^ d f 05 o ® tJ d © <T> if\ KN o\ m o ® o XI * • • • • • •
<D ® o. lO vo a H tH OS g d a <M Si Q 4»
H fli o CO <»-» m
• « EH O . 13 « t«Q a ce -P e ^ 03 m CQ
{3 >» t«Q a ce -P o o o O o o O S Ti KA o o- CM \o JO o 03 lf\ HI fj ffl 9 a o rt X) 9
-H-H « 4 • d «D H 9 la
a> o n M d o d » as U 1 •
d aj+» •H H o •s U CD o ^ pS o 3) a> • n n AO) 0} a d +» ^ U a 4» Jo +» ^ d <D ctl <B W , o o S as a
•©jands TmeH . d N ajtatide-praeH a* o a -p trjaii!j.Tiog
l a t i t u d e are found and t h e i r d a t a a re shown i n
l a b l e e V^ and 20. I t i s f o r the same
- l a t i t u d e , tiie phuses of the diurneil and t h o s e of
the e e a i - d i a r n a l cocponents of t he d a i l y v a r i a t i o n
- a t h i ^ e r a l t i t u d e s . Th i s i s t r u e
bo th f o r meson S^d n e u t r o n phase s .
4 .4 B i s c u s s i o a
The f a c t t h a t t h e ampl i tude of t h e d i u r n a l
v a r i a t i o n i s very small on t h e p o l a r l a t i t u a e s
s u g g e s t s t h a t t h e v a r i a t i o n i s not caused by a n i s o t r o p y
of j j r i m ^ y o o s a i c - r a y s over t h e e n t i r e energy r a n g e ,
Hossrever, t h e r e appears t o be a c e r t a i n t h r e s h o l d i n
eTnar^ ^spectrum below which t h e r e i s no c o n t r i b u t i o n /
t o d i i i r j i a l v a r i a t i o n . Table 21 shows t h a t t he ampl i -
t^de'^-^f the d i u r n a l and aemi -d iu rna l components of
•%he d a i l y v a r i a t i o n a re l a r g « r i n t h e caee of n e u t r o n
I n t e a j s i t y t h a n f o r meson i n t e » W t y at ©( jua tor ia l aa
wel l as p o l a r l a t i t u d e s .
At t h e e c i u a t o r i a ^ l ^ t t t e i d e s (2°3) and t h e
p o X a r . 8 3 ® H ) l a t i t u d e s , ^ t h e r a t i o between
thf^amplitudea of the d i u r n a l component of n e u t r o n
and ig^son i n t e n s i t y , i a of t he o r d e r of 2.50 snd 1 . 7 7
r e s p e c t i v e l y . For tho rfemi~diarnal component of t h e
51 0
0*H tt n ^ ©
2 O-H
o o
m §• o
n m (D
•O ^ I ® •H ^
41> (0 O fJ
fl a H.ffl-P
04a
0<N
<D ^ at o aJ -H
l l
I t I
^ • CS • _ Q41 JCj H 6
09 S] o
^ ^ B 1 I d o 9 d • M-H O ^ o o t) o 14 vt • a « Q 5 ® H a p f^ JC{ a o ® Oi4* P Oi
I • S i ^ A S t ; n O
^ ^ « -H H O P
+> o o t>
4» B
-H-H^* « <D » 6
o C2)
o •H +» to
I
vo
Uf\
00
— 5 -vO 01 CM CM
H
r-CM
0 vo 0
• KN •
CM o>
o vo • tr> CM
o
ri CM
w • § ^ o
P I O O P I
H O
m
e-o
<T> CM
<D "ti-
er* CO • •
ov NO • •
vo t*-H H
cr% 00 • •
t - o H
T5—ap-ir> vo CM CM
T5 ZT" 00 CM •-4 VO H H
o t -VO CM g?
K\ H eo o CM H CM
O in o o O H tn K\ R
o o CM O • •
00 cr>
•H On ES to
i a ta C9 •H 0)
% ^ tn ir\
CM
s
I P I 1
% +»
O
a I
i £-1
t> to <D «
^ M O O m +» a d © ffl Td
ffl
§ +» m di
05 ^ pki ffl '
I
o o «
O O H B) $3 ai <D o ® ra ^
j j 03 aJ >H
8 4 9 g I I S S ^ a . ® ca -H o 4 ^ OJ (D <t3 O -H I P Ot-^ -H f j ® ^ ^ i 2 St Td SSI « KJ o « -H o O q
h a I « O 5J Q <
(D <£> 'tJ <N ® a H =N O OS ® (O
— j
o ts s o a J pst a 0) s a 4» O ai-Pig q ff, ^ U I o a ••H H 0+» p o "o o a 0] (B (t (B rH $:J fM rt O)
^ CJ m U 0
H - H - t a 9 O w s
9 tJ $ U a o
(D
9
-e •H
Hi
a o
4»
I
CM
H « r4
VO O
H CO H
o o CTi VO trv t> CM CM
VO c-" VO CM
o ' o CM O GO ON
9 S +» P. (S
M
m 09 •H (D
tr\
O u>
CM • iH iH
cr> cr> CM H
O O r-f cy» H fH
t< 0 5 CM CM
H O
o o o o ITS o H • • o lf\ CM H ff\ K\ <y» as
o o 00 c -m in
• 4» S3 U I o, fH
CM
a} I -p c
1 '
3 3
1 9 a
I - H
O O in a> <»
d 6J -C! H
•H - P
CO Xi +» ^ o
O S3 o o ©
CD - H
-P ^ ^ •H H ffi « (>H
® •HH +3 t j O, d ® t j ® g 0) Q
o o a ^ "H (D U O-P o 12 2 ** d pj o
CVJ «
CQ
tJ
O t)0 c f l o
o VO H l f \ H O
• • • • CM H CM CM
OT O O o
CM o KN t - <0
H
O •s u o
>5 4»
•H
- P
O +»
o o
•X3
•H
S i ®
a ®
® a
H O ® hi
d
>5 •P •H 0) ®
•H
d o
+ »
§
•H a d ®
hH
® ®
®
H p
®
^ i g H Oi
0
03
f
I
CM Pij
86
d a i l y v a r i a t i o n , t h e r a t i o Eg a t e q u a t o r i a l and t h e
p o l a r l a t i t u d e s i s about 4 .5 and 4 .0 r e s p e c t i v e l y .
Th i s shov./s t h a t t he E a t i o i s l a r g e r f o r t h e
s e m i - d i u r n j ^ component t h a n f o r the d iu rn t . ! component
of t he d a i l y v a r i a t i o n .
CHAP!E£& V.
SIUDY Qg THE DAILY VARlAlIOlf Qi COSMIC &AY IHIENSI!CI OH MASBi glCALLY mSTURBED AHD QUIET 13AYS.AI mg^'EREHI
LATITUDES I S BOTH THE HSal S P H l ^ S .
The s tudy of t h e ampl i tude and phase of t h e
d a i l y v a r i a t i o n a t d i f f e r e n t l a t i t u d e s i n bo th
t h e h e m i - g p h e r e s p a r t i c l u a r l y on m a g n e t i c a l l y dis-fco/^beci
tiiPl bated and q u i e t days pro v i a e s an i m p o r t a n t t o o l t o
examine t h e energy spect rum of t h e pr imary a n i s o t r o p y
r e s p o n s i b l e f o r t h e d a i l y v a r i a t i o n . From t h i s s t udy
we can l e a r n about t h e v a r i o u s i n f l u e n c e s on c o s m i c - r a y
i n t e n s i t y a r i s i n g from t h e e l e c t r o m a g n e t i c c o n d i t i o n s
of i n t e r p l a n e t a r y space and of t h e sun . fiowever, such
a s tudy i s d i f f i c u l t because of l a c k of cosmic r a y 1 2
da ta} a l t h o u g h some r e s e a r c h g roups ' have a t t e m p t e d
i t e a r l i e r .
Recen t ly f t h e I .Cr .Y. , c o s m i c - r a y meson
t e l e s c o p e s and n e u t r o n m o n i t o r s a l l o v e r t h e wor ld
have p r o v i d e d d a t a which may De u s e f u l l y a n a l y z e d .
We a n a l y s e d t h e p r e s s u r e c o r r e c t e d d a t a of n e u t r o n
and meson i n t e n s i t y f o r t h e I . G . Y . s t a t i o n s g i v e n
i n T a b l e 12 .
1 . H . E l l i o t , P r o g r e s s i n Cosmic-ray p h y s i c s , i , 4 5 5 ( 1 9 5 2 ) 2 . V . S a r a b h a i , and®.W.Herurkar, Annual , Hev. N u c l e a r ,
' S c i . , 6 , 1 , U 9 5 6 ) .
88
I n o r d e r to s tudy t h e n a t u r e of t h e d a i l y
VcaTiation of t h e co smic - r e^ meson and t h e n e u t r o n
i n t e n s i t y on d i s t u r b e d ana q u i e t d a y s , we have
averaged both meson and n e u t r o n i n t e n s i t y d a t a o f
a l l t h e s e tv/o t y p e s of jdays s e p a r a t e l y f o r t h e p e r i o d
J a n . t o Dec. 1958. Then u s i n g t h e 12 h i h o u r l y v a l u e s
f o r t h e two d i f f e r e n t t y p e s o ^ d a y s , f i r s t and second
harmonic components have been c a l c u l a t e d . I n t h i s
way meson and n e u t r o n d a t a have been a n a l y s e d and t h e
r e s u l t s a r e g i v e n i n T a b l e s 22 to 25.
5 . 1 DIUaHAL VAaiAgios OH MAGHEIICALL^ msTURBED AHS QDIEg DAYa.
Prom Table 22, i t i s d e a r t h a t a t p o l a r
l a t i t u d e s ( >s =85°H, X = 75®S) t h e d i u r n a l a m p l i t u d e
of t h e meson i n t e n s i t y i s a lmost t h e same on
m a g n e t i c a l l y d i s t u r b e d and q.uiet days . At o t h e r
s t a t i o n s i n t h e n o r t h e r n h e m i s p h e r e , Ot tawa (57°N)
C h u r c h i l l (70®H), i t i s found l a r g e r on m a g n e t i c a l l y
q u i e t days t h a n on d i s t u r b e d days'^.* The same was
o b s e r v e d by Sekido , e t a l . (1950)^ a t Nagoyo (>v«25®K).
However, Hogg (1949)* , i n t h e case of t h e i o n i s a t i o n
5 . y . S a k i d o , M.Kodama, and T . I a g i , R e p t . I o n o s p h e r e , A e s . , J a p a n , i , 207 (1950) .
4 . A.ft .flogfa., MemSiirs of t h e common w e a l t h o b s e r v a t o r y , Ho. 10 ( 1 9 4 9 ) .
t The a u t h o r a t Gulmarg ( X « 2 4 . 7 H) a l s o oDserved t h a t t h e a m p l i t u a e i s l a r g e r on q u i e t days t h a n on t h e d i s t u r b e d d a y s .
126
<M CM I
%
ITN o r- UN cr> o 00 aj-j • • • • • • • • o S'-i o o CM <Tv KS irt H VO S'-i H r-4 iH H H i-i o ^ o • VO VO o CM VO IfN o H c5 H H r-l H H ^ o O O O O O O O O d flrf •o • • • • • • • tzin O O. o o O o o. o •H 5' 5' 1' n <j> H CM VO m 1' A H H CM CM CM • O • O • o • O • O • O • O • o a • o U o 1-4 00 t- K\ • • • • • • • « « o m J <0 ey CM CM J <0 H CM CM CM o-o •
s tJ *£> VO o K\ CM VO ITS O s tJ -a H H c5 1-4 H H r-l to O O O o O O O O o •p • • « • • • • « •H O o. o o o O o o CO 4> H 2" A' 8' U 09 g H 8' lf\ o H tr\ H « C\l • CM • CM • CM • • •
CM • O o O o o O O O • > • O cfiu b * i n HN U\ in t- C 3 t4 r-l H H H r4 H H
• • 1 • • • • • CO o o O 1 O O O O O ® 4) P« ^ Q •H o o +»
* m tzs to £0 09 to CO a ed o o o O O o o a o c- CM VD H KN o <D m H VO o <D cS
• • fl H • * 0) o 0 H 00 •H T4 •r4 • h • •H JC3 oi Q> {2 d a oJ rH o g ^ 3 d o -P O H 0) 0 • o" e> M (S 0 1 4» +» § s « o «J S m o o w a a
ft o u
o t a o P i g O •
m o a> 04» S t-i ^ ^ Xiri -P +» OJ fl
^ «M ® ^
O oj ® -O 00 « 03 "CJ Xt h Q. O o •cJ a> 1
•p rt •H « 1-4 42
(30 CO
o
PM
1 ea §1? o t - o o xt • • • • • • • oJ^ <o CO H a\ lA CO O O XJi i-l rA f t f-i a. Q m cn OV tn ON S o o o O H CM S § ^ TJ o o o o O O o d o * • • «» • • • • o. o- o . c. O o. o •H H rt* i : Q O P4 VO "t {SI i : us t -U 1 H tf\ 04 K •H O • • • • • • • p!i fa, o o o o o o o
ro
O ^ ® o - trv tf\ as cn o o o nj:s • • • • • • •
O H s lA vO O CVi w
o ffl , CT» CT» cn m ON o 4> O o o 1-4 CM CM ® -txt rt tJ o o o o O O O ® -txt rt d « • • • • • •
o 43 o. o . o. o o o o «J +»
•H A' cJ* A' Oi vo o ON IfN 00 H •H 2 i CM iH H CM KN
• « • • • • • O o O o o o O
t4 Q} m « H Xt M o a •Heo KN KN <M t - CM CM H •Heo C- t - C- m t -ca<M 1 ® • • • • m • • O 4) p. o o o o o o O o fMO
i » » » CO 03 to CO & • o o o o O o o o t - CM VO 0) cl CO lA ciJ
• •
H « • • (0 H <9 to T» •H • U • o 0 Xi cd O 3 a •H H o h 3 o O aJ o • a S! m 4» » U 5 +» 4» O OS 05 s O a W a
91
ca \
64
si
o rf n o O 3 U o
o fl o+» o -H ID m « (S 43
a> 2 ^ a} (D ^ si a ,
"tJ o C? o
^ CO •P -H
i >>
Cl TJ ® "Ct ft m p a> jcj 45 o -H (D ^ 3} P4 O H
a> ftS +»
•H H O* 4
O § CO
ir\ 00
o CVJ tA O 00 K\ • • • o o ^ r4
cr\ CT» in cr> KN o o O o H CM CM o o o o o O O • • • • • « •
o . o . o o . o . o o A' 4 ' CM CM CT\ 00 CM o CM H O o
• • • • • » • O o o o O o o
CJ si t - o o O o J • m -t cn oo H if\ m CliflJ « « • • • • o ^ OS O O o H t<-\ H O "Xi Xi i fM ^ f Xi i fM ^ -H ® O a ^ as cn lA m S o o O CM S d m o o o O o O O n • • • • • • •
0 o . o . o o . o o o . +1 +1 +1 j-y M •i-t ri ri •H § t i m o o H VO § o CM o\ 00 o Oi H CM CM o H o {| » • • • • # • m o O o o o o o
S • TJ 12! ts iz; 02 OJ O o o o O o o KN o CM VO K\ 00 lA H o-^ (D cS
• • H • 0) r-t v> d •H • ^ • o Jj OS a> a
fHI M a h w O 4a. O ^ <a o a n OS 03 •p « » (D a +» CO « (d
1 o o 3 m m
6> 3 a
0) t3
•H H Q»
o O (TV O o O o <7» CO vo
• • « • • • • • 00 O o CM i r \
v o v o o CM vo t n o H H CM «— r » r -O O o o o O o o
• « • • • • • • o o o o o o o . o . + 1 S' + 1 + l S' o o o CD 00
KN 00 o t>- (Ti IfN CM O ; o CM O O t— o O
• • • « » • • O o o o o o o o
• KS O ® u 03 ^ VO <D CM CM ® u 03 ^ * » • • • • • OJzi o rH O o
I H I
92
\ o K \ CM vo irv o i H
O O o o O o o o * * • • • • • •
o . o o o o o o o + 1 + +1 + 1 +! -i-l
H o o vo CM vo 00 00
o i H CM o r— a o o 'a • • # • • • •
o O o o o o o o
» » 5z: t o 05 m ra ea o o o o O o o o
o t - CM ^ r v 00 i r . VO
• •
H « • •
© X H a> !» •H -H •H • • • ^ Si OS © S a H O ? u CO o O cts 9 • o* 0) GO S! •p o o ? O ^ +> B5 (D (0 d
01 O o a w
bO cfl a o (!) C3
O •H
93
a
• • o e * - t n tf • • • •
CM t - c -• r 4 r-t
>* e
' d " ^ ' c Q ' d rt PJ CPk ^ o cvt O i 0 0
• a 0 0 0 0 - H SJ • • • «
0 0 0 0
m d & ^ f - « + 1
t r » ^ P S3 a ot CO CM
0 € # # • +>
0 0 0 0 0
V I n o o CJ
• • t o
• a t • a OS •
t * -• i n • • ffl ^ C J if\ e - m
d ® (k H O o "CJ
(k o sJ ®
p j ® 4 9 0 a - H d p j ® 4 9 0 a - H d
P i •
C o ®
4 3 m C o ® CD CM CVJ 0 0
^ 0 • 0 • 0 • 0 «
0 Pi • r4 0 0 , 0 © ^ 0
f H a
0 r H P< S!
Co CO Q) 4
CNJ CM H 4 • •
0 •
r » • n
• a {Q S
H rt 0 H H K N
' C t ' d • P ® 0 r - l
© C J S a
C J - t J CVJ CM 4 * •r< 0 r - l ^ •
a 1 W5 d 0 0 0 0
0 <8 0 t — 0 0 c - CO « e-ri-H i n U N I T l
§ ® as + » © C!3 flo rt fl a> 0 rt fl a> 0 0 rt PI • ^ 3 0 OS a 3 •
f M 0 ^ • m
f M 0 a A a a a) +=» H a - p r - l •f
0 a + » 0 a
• q . H S T I O d W O 0 • ^ . t t e m o d M O O
T t o e e H a o a ! | . t t 9 | |
9 4
I
ca ® 'tf
a
®
* <w 0 o <a cj (0 ^ o <D
•rl'5
^ -H -H
® >>'•5 01 d
CO - H ®
%
^ 15
•H d +» H © -H Qt ri O S o d <3 0< Q}
(S •p o d
d o u o n +» ^ ^
O
T»
d
« eg oc c
^ a
d o c £
t3 tB 4» d © -.-( H 4» •P ®
® .'O iS+» a-H O - P (D 03 cbH
d • o 3t 4> «s 05 o
a si o Pk {3 o o
* *
O tfN jd
0
1 JSL.
CM O •
I-o » O CO O H O H Cd CM o o
• * o, o. OJ H
• •
o m CM CM
l A
CO CO
ON o o ^ o *
A
o% o o * A'
JQ. o * H
O o
cr\ o o •
CM
cn o o #
CM «
O
H O H CO CM CM
o o o o t - 03 00 m tn ir\ m
I iH
CD I O
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S o, r-l
J d o O £i ta s » o a o
•p ^ d d <t> o d o +» Q, a o o K O
9 tj
CJliamber d a t a and Wada (1950)^ l a t h e case of meson
i n t e n s i t y d a t a obse rved t h a t t h e ampl i tude h a s n e a r l y
t h e same v a l u e on d i s t u r b e d as we l l as q u i e t days .
I n t h e s o u t h e r n hemisphere a t Makerere (2°)
Lae (16®), Hermanus (33°) and Maquarie (61°) t h e
ampl i tude i s l a r g e r on m a g n e t i c a l l y -quie-t days t h a n
on q u i e t days .
I n t h e case of the n e u t r o n i n t e n s i t y , t h e
ampl i tude i s l a r g e r on m a g n e t i c a l l y q u i e t days than
on d i s t u r b e d days a t a l l the d i f f e r e n t l a t i t u d e s
i n the s o u t h e r n hemisphere . But , i n t h e n o r t h e r n
hemisphere , a t Ottawa (57°) > t h e d i u r n a l eaaplitude
i s l a r g e r on q u i e t days th£ui on t h e d i s t u r b e d days;
Tshile a t o t h e r h i ^ e r p o l a r l a t i t u d e s , ©hurch i l l
(70®) and Reso lu t e (83°) the eaaplitude i s l a r g e r on
d i s t u r b e d days tJaan on q u i e t days . She d a t a i s
summ^zdzed i n Sab le 26.
5 . 2 IHE PHASE OF THS BIPESAL VAHlATIOg 6H DIS5UEBEB AHD QUIBT PAYS.
The phase s of t h e f i r s t harmonic component
of meson and n e u t r o n i n t e n s i t y a re g iven i n l a b l e s 22 & 23*
5 . M.Wada, Read a t t h e seventh General Meet ing of Soc. !Eerr. Mag. <1: £ l e c t . J a p a n , 1930.
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9
From Table 231 i t i s c l e a r t h a t t he phase f o r
n e u t r o n s i s s m a l l e r on d i s t u r b e d days t h a n on q u i e t days
a t d i f f e r e n t l a t i t u d e s i n t h e n o r t h e r n hemisphere , *ftiile
a t d i f f e r e n t l a t i t u d e s i n the s o u t h e r n hemisphere t h e r e
i s no s y s t e m a t i c r e l a t i o n .
i n t h e case of t h e meson i n t e n s i t y , i n t h e
n o r t h e r n hemisphere , a t l a t i t u d e s 85® and 70° the
phase i s s m a l l e r on d i s t u r b e d days t h a n on q u i e t days ,
excep t a t Ot tawa { m 57^U), vdaere i t i s t h e same on
both t y p e s of days . I n t h e s o u t h e r n hemisphere , a t
a l l t h e d i f f e r e n t l a t i t u d e s t h e phase i s e a r l i e r on
q u i e t days t h a n on d i s t u r b e d days . Thus t h e n a t u r e
of the phase on d i s t u r b e d days and q u i e t days i n t h e
n o r t h e m hemisphere i s o p p o s i t e of what i t i s i n t h e
s o u t h e r n hemisphere .
The v a r i a t i o n of t h e phase of meson i n t e n s i t y
i n t h e n o r t h e r n hemisphere i s s i m i l a r to was a l r e a d y
r e p o r t e d by Hogg (1949) ^f Wada (1950)^ and Selcido e t a l .
( 1950 )^ .
5 . 3 Sm~IP0&5AL CQMPOHEHT OK PI STUBBED AHI> QUIET BI^S.
I n t h e case of the semi>d iu rna l components of
meson and n e u t r o n i n t e n s i t y ampl i tudes and phases a r e
shown i n T a b l e s 24, 25. I t i s c l e a r from t h e s e t a o l e s
t h a t t h e ampl i tudes are q u i t e s i g n i f i c a n t a t v a r i o u s
l a t i t u d e s i n both t h e hemispheres .
At a l l t h e n o r t h e r n and sou the rn l a t i t u d e s
examined h e r e , t h e s e m i - d i u r n a l ampl i tude i s l a r g e r on
a
9?
m a g n e t i c a l l y d i s t u r b e d days t h a n on <iuiet days ,
excep t a t Mawson ( 7 3 ° 3 ) .
The semi-diurnal ampl i tude a t d i f f e r e n t l a t i t u d e s
i n Doth t h e hemispheres a l s o ahoAs t h a t i t i s l a r g e r
on m a g n e t i c a l l y d i s t u r b e d days than on q u i e t days,
exoept a t Hermanus ( X ® 54^3) where t h e change i s
o p p o s i t e i n n a t u r e , ih, iaA>:b*du
Sab le 54 shows t h a t a t a l l t h e phase of t h e A
n e u t r o n i n t e n s i t y y A - a t i t u d o c i s e a r l i « r on d i s t u r b e d
days t h a n on q u i e t days , excep t a t Lae ( X = 16®3)
where the change i s o p p o s i t e but s l i ^ t . The phase of
t h e semi-di^i rnal component of » e s o n i n t e n s i t y does n o t
show any s y s t e m a t i c and c o n s t a n t behaviour a t a i f f e r e n t
l a t i t u d e s a s i s shown i n t h e case of t h e n e u t r o n s .
Here* t h e phase i s a l s o e a r l i e r on d i s t u r b e d days
t h a n on q u i e t days excep t a t C h u r c h i l l (70*^5) and
Macquarie ( 6 l ° S ) \ ^ e r e i t i s e a r l i e r on q u i e t days ,
5 . 4 ALMUJ3B PJSP-ENBgjJ B OF OM HISTURBBB i^D QUIBI DA^S.
^ o m Hable i s n o t i c e d t h a t i n t h e
caae of both meson and n e u t r o n i n t e n s i t y t h e phase
o i t h e d i u r n a l v a r i a t i o n i s e a r l i e r a t h i g h e r
a l t i t u d e s f o r t h e same l a t i t u d e s . This f a c t i s
a l s o found on m a g n e t i c a l l y d i s t u r b e d £uid q u i e t days .
3-8
2!ki8 I s i n agreement with our r e s u l t s i n Chapter IV.
!fhe phase o f the a e a i - d l u r n a l v a r i a t i a n of
n e u t r o n i n t e n s i t y i s a l so e a r l i e r a t h i ^ a l t i t u d e s
f o r t h e ssaae l a t i t u d e s on both t y p e s of days . But
f o r meson i n t e n s i t y t h e s e m i - d i u r n a l phase shows t h i s
n a t u r e on ly on m a g n e t i c a l l y q u i e t days .
5 . 5 CQMPAEAgiyi; srJBY OF TUB EATURE QF DAILY YAElAflQH Qif CQ^IC £A^ IMI^fiSIIY AT DMFmMSMf IH H3IH TOE
The n a t u r e of t h e average d a i l y v a r i a t i o n
of t h e meson and n e u t r o n i n t e n s i t i e s a re examined
on magnetL c a l l y d i s t u r b e d and q u i e t days s e p a r a t e l y
a t d i^ f fe ren t l a t i t u d e s on bo th s i d e s of t h e e q u a t o r .
The cu rves r e p r e s e n t i n g t h i s average d a i l y v a r i a t i o n
a re g iven i n f i g . 29 to 32,
5 . 5 ( a ) DAILY YARIAflOa OH BISggRSSB BATS
!Ehe c u r v e s i n f i g . 29, show t h a t the
average d a i l y v a r i a t i o n of t h e n e u t r o n i n t e n s i t y , on
m a g n e t i c a l l y d i s t u r b e d ds^st a t d i f f e r e n t l a t i t u d e s
i n both t h e hemispheresf h a s two maxima and two minima
A and B. !I!he minimum A p r e c e d e s the midnight ma:£iaum
by about an hour a t a l l the l a t i t u d e s except Makerer*
and La.e (16®S) ^ e r e i t p r e c e d e s by about two hours .
S.
<#4 \ RfSOit/Te ( ) 1
\ 1 t^o a
\ ® A !
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f i ^ Z f . HooRS /A' t / r Tw / f k f f f ^ ^ e o / t t t y o r M^nrmM
o / j T i / ^ e s p om^s^ jQr a m n m f r L^TfTi/OfS.
99
I n t h e n o r t h e r n hemisphere t h e d a i l y v a r i a t i o n ,
of n e u t r o n i n t e n s i t y i s of s i m i l a r n a t u r e on a l l t h e
l a t i t u d e s examined h e r e , hav ing two maxima (one a t
m i d n i ^ t and o t h e r between 1800-2000 h r s ) and two
minima A and B. The second broad minimum fi o c c u r s a t
about 1100 h r s . U.T. (between 0900-1500 h r s . ) .
I n t h e sou^ the rn hemispheres t h e n a t u r e of t h i s
d a i l y v a r i a t i o n does not show t h e same f e a t u r e a s
obse rved i n t h e n o r t h e r n hemisphere . Here the second
maximum B o c c u r s a t about 1500 h r s . U.S. (be tween
1100-1500 h r s . ) .
Another p o i n t which i s appa ren t from t h e cu rves
i n f i g . 29f i s t h a t the gene ra l n a t u r e of the d a i l y
v a r i a t i o n of n e u t r o n i n t e n s i t y i n t h e n o r t h e r n hemisphere
i s o p p o s i t e to t h a t of the d a i l y v a r i a t i o n i n t h e
s o u t h e r n hemisphe res .
Prom t h e curves i n P i g . 50, which r e p r e s e n t
t h e d a i l y v a r i a t i o n of meson i n t e n s i t y on d i f f e r e n t *
l a t i t u d e s i n both the hemispheres , t he f o l l o w i n g p o i n t s
can be drawn s -
( i ) On a l l t h e l a t i t u d e s t h e d a i l y v a r i a t i o n of
meson i n t e n s i t y shows one maximiuB a t m i d n i ^ t and i s
p receded by a minimm A, which i s sharp i n t h e x i s r the rn
TMf/Jtfft^e omv VMtMTlOM Of Mesa^ '' COMfW^f/r or COSmC'Mftr t^TCMStfKOM
M/iAM I'cmiY otSTtMtilo Dt^ys.^r Curr/M/A/T l^TfTt/OfS.
100
hemisphere axid sha l low i n t h e s o u t h e r n h e m i s p h e r e .
(2) lEhe second b road maximum ( i n t h e a f t e r n o o n )
i n t h e n o r t h e r n hemisphere s l i d e s t o e a r l i e r h o u r s
a s t h e e q u a t o r i s approached .
(5 ) The second minimum B i n t h e n o r t h e r n h e m i s -
phe re a l s o s l i d e s s l i g h t l y to e a r l i e r h o u r s a s t h e
e q u a t o r i s approached and i t i s s h a l l o w i n h i ^
l a t i t u d e s .
( 4 ) But f o r Hermanus { X » 54*^3), t h e second
maximum and minimum a r e h a r d l y n o t i c e d i n t h e s o u t h e r n
l a t i t u d e s .
(5 ) I n t h e n o r t h e r n hemisphere a t a l l t h e l a t i t u d e s
the d a i l y v a r i a t i o n of meson i n t e n s i t y a l s o snows a
s i m i l a r i t y i n n a t u r e , h u t t h i s i s n o t o b s e r v e d on t h e
l a t i t u d e s i n t h e s o u t h e r n h e m i s p h e r e .
5 . 5 ( h } DAILY YAsHASlO^ OS UUIEI PAX^
The f o l l o w i n g ^ p o i n t s may be drawn f rom t h e
n a t u r e of the d a i l y v a r i a t i o n of meson and n e u t r o n
components , on que t days , a t d i f f e r e n t l a t i t u d e s
i n b o t h t h e h e m i s p h e r e s .
(1) IThe c u r v e s i n P i g , 31 , show t h a t t h e d a i l y
v a r i a t i o n s of meson component g e n e r a l l y have on ly one
maximum and one minimum.
Pi /.S '-VT
(f^UUfHUt
SlMfWf Mt
<6'' S)
W o r TH( O/ftlY Of MFSOf* COAfj»t>\^£A/r a/' cajM/c-fi/iY /A/TfA/srry, a/^ M^GKCTlCrtllY ^V/fT O/fyf, ^^ O/ffffifA/r t/97/rt/0£S.
10
(2) I n t h e n o r t h e r n hemispheres t h e maximum i n
the even ing s h i f t s to e a r l i e r hoiira a s t h e e q u a t o r i s
approached and i t becomes sha rpe r i n t h e r e g i o n of
57® l a t i t u d e .
(3) I n t h e s o u t h e r n hemispheres t h e maximum and
minimxam become s h a r p e r a s v/e move away from t h e
e q u a t o r , f h e t ime of t h e s e maxima and minima a l so
changes back gind f o r t h a s t h e p o l e s a re approached.
(4) The d a i l y v a r i a t i o n of meson i n t e n s i t y , on
q u i e t days , shows a s i m i l a r i t y i n n a t u r e , on d i f f e r e n t
l a t i t u a e s i n t h e n o r t h e r n hemisphere . But i t i s not
obse rved i n t h e s o u t h e r n hemisphere where t h e d a i l y
v a r i a t i o n i s d i f f e r e n t a t d i f f e r e n t l a t i t u d e s .
(5) The cu rves i n F ig , 52, show t h a t t h e d a i l y
v a r i a t i o n s of n e u t r o n component a l s o have one"maximum
and one minimxim on a l l t h e l a t i t u d e s i n bo th t h e hemis -
p h e r e s except a t t h e e q u a t o r .
(6 ) I n t h e iu>rthern hemisphere the maximum remains
a t 23 h r s . upto l a t i t u a e 58® and t h e n s h i f t s t o
e a r l i e r h o u r s a s t h e equa to r i s approached. The
minimum a l so s h i f t s to e a r l i e r hou r s and becomes
s h a r p e r as equa to r i s approached.
(7) I n t h e sou the rn hemisphere t h e maximum s h i f t s
- • i
fftiOCUTT (Si'M)
AK/'TV AMC < C V V
s/n/rpohJ r ' a/ ^ost^fC-^^Y /A'/Z/VJ//^J/V -V/ V R / V 4FOFET D//yi, ''/r Of/ f / f f f Af 7 l/7r/Ti/ors.
102
t o e a r l i e r h o u r s very much l i k e the s h i f t of t h e
miniiBUBi i n t h e n o r t h e r n hemisphe res .
(8) Proa t h e ciirves i n P i g . 31 & 32, one may say %
t h a t t h e d a i l y v a r i a t i o n of meson and n e u t r o n i n t e n -
s i t i e s show a s i m i l a r i t y i n n a t u r e amongst t h e
d i f f e r e n t l a t i t u d e s i n t h e n o r t h e r n hemisphere , b u t
i t does not show t h i s s i m i l a r i t y i n t h e s o u t h e r n
hemisphere .
5 , 6 D i scuss ion Aim Qg &ESULTS.
(1) f h e ampl i tude of t h e d i u r n a l component of
t he d a i l y v a r i a t i o n of t h e cosmic-ray i n t e n s i t y h a s
f r e q u e n t l y been c o n s i d e r e d an index of the degree
of a n i s o t r o p y of pr imary r a d i a t i o n .
f a b l e 28 shows t h a t the d i u r n a l ampl i tude
of th® d a i l y v a r i a t i o n observed wi th t h e n e u t r o n
moni to r i s g r e a t e r t h a n t h a t obse rved by the meson
moni to r a t low and h i g h ' l a t i t u d e s i n both t h e hemi-
s p h e r e s . (Thus i t shows t h a t t h e a n i s o t r o p y i s g r e a t e r
i n the spectrrim i n t h e mean energy r ange of about
7Bev (which i s measured by a n e u t r o n moni to r a t
middle l a t i t a d e s ) t h a n i n the spectrum with a mean
energy of about 40 Bev. (which would be measured a t
103
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104
a s i m i l a r s t a t i o n with a meson i n t e n s i t y m o n i t o r ) .
l a b l e 28 a l so shows t h a t t h e i i a t i o ^ i s l a r g e r a t
e q u a t o r i a l l a t i t u d e s a s compared to t h e h i ^ e r
l a t i t u d e s *
(2) A l f v e n ' (1950)^'"^ e x p r e s s e d t h e h i g h l y
impor t an t concept t h a t c e r t a i n a n i s o t r o p y of cosmic-
r a y s may be due to the a c c e l e r a t i o n and r e t a r d a t i o n
of p a r t i c l e s i n t h e f i e l d s of t h e c o r p u s c u l a r s t r eams
e m i t t e d by t h e sun.
Q
E l l i o t and Dolbear (1951) have sugges t ed
t h a t t he s o l a r d a l l y v a r i a t i o n i s due t o t h e a n i s o t r o p y of
t h e pr imary r a d i a t i o n c r e a t e d by t h e i n f l u e n c e of t h e
c o r p u s c u l a r s t r e e m s e m i t t e d by t h e sun, on pr imary
r a d i a t i o n .
According t o E l l i o t and Dolbear (1951)^ ^ o
have vsorked ou t some conse(iuencea of the t h e o r y , i t
should l e a d to a dec rease i n i n t e n s i t y i n t h e l a t e
morning aJid an i n c r e a s e s h o r t l y a f t e r t h e noon.
Th i s c o n c l u s i o n i s i n q u a l i t a t i v e agreement wi th t h e
e x p e r i m e n t a l r e s u l t s a n a l y s e d h e r e f o r the n o r t h e r n
l a t i t u d e s (shown i n . The d a i l y v a x ' i a t i o n
obse rved on m a g n e t i c a l l y d i s t u r b e d days i s i n very
c l o s e agreement with t h e above i n t e r p r e t i a t i o n . doYi-6 . H .Al fven , Cosmical E l e c t r o d y n e m i c s ( 0 x f o r d ) C h . T I , ( l 9 5 0 ) . 7 . H .Al fven , Phys .Eev . 1752 ( 1 9 4 9 ) . 8 . H . E l l i o t , and D . W . N . ^ l b e a r , J . A t m o s . T e r r . P h y s . i , 2 0 5
( 1 9 5 1 ) .
105
e v o r , oa r a n a l y s i s Tor t h e a o a t n e r n i iemisphere
does not bear t h i s out»
j a i l o t and Dolbear (1951)^ a l s o i n d i c a t e d
t h a t t h e ampl i tude of t h e d a i l y v a r i a t i o n woiild Do
l a r g e r on m a g n e t i c a l l y d i s t u r b e d days . They showed
i t t o be so from t h e i r r e s u l t s f o r a minimum s o l a r
a c t i v i t y p e r i o d . Th i s h a s been found t o be g e n e r a l l y
t r u e f o r oa r d a t a , v^nich i s f o r the p e r i o d of maximum
s o l a r a c t i v i t y . Bat t he d i f f e r e n c e between t h e a a i l y
v a r i a t i o n on d i s t u r b e d and q u i e t days i s l a r g e r d u r i n g
t h e p e r i o d of minimum s o l a r a c t i v i t y .
I t i s s i g n i f i c a n t t o p o i n t ou t t h a t a t some
of the l a t l t a d e s the v a r i a t i o n appea r s t o be l a r g e
on q u i e t days t h a n on d i s t u r b e d days . S h i s anom^y
caniiOt be e x p l a i n e d by t h e above h y p o t h e s i s a s
such , f h e need f o r a more comprehensive t h e o r y of
c o a a i c ray a n i s o t r o p y i s h i g h l i ^ t e d by t h e s e r e s u l t s .
lOS
CaAI>!EE& — YI.
THE IKFLUEHOS OF S&lALL SOLAR FLAfi^S ON TEE ISTEmiTY OF THE HARD CQMfOSJSM? OF
GQSMIG RABIATIOE.
The s tudy of i n c r e a s e s of cosmic-rety
I n t e n s i t y a s s o c i a t e d vidth l a r g e soXar f l a r e s h a s
p rov ided v a l u a b l e i n f o r m a t i o n r e g a r d i n g t h e i n t e r -
p l a n e t a r y megne t ic f i e l d s , p r o p a g a t i o n of charged
p a r t i c l e s from t h e sun to t h e e a r t h and t h e energy
spectrum of s o l a r f l a r e p a r t i c l e s .
Al l t h e f l a r e s which were obse rved i n t h e
p a s t were of h igh impor tance and t h e c o r r e s p o n d i n g
i n c r e a s e of cosmic- rsy i n t e n s i t y was obse rved a t a
number of widely s e p a r a t e d s t a t i o n s . The f i r s t
cosaiic«>ray i n c r e a s e a s s o c i a t e d wi th a s o l a r f l a r e
was obse rved a t a number of widely s e p a r a t e d p l a c e s
on Feb. 28 and March 7 , 1942 by Berry and H e s s ( l 9 4 2 ) ^ , 2
and Lange and Forbush (1942) . O the r s i m i l a r i n c r e a s e s
were observed on J u l y 25, 1946, and Nov. 19, 1949, by
Forbush (1946)^ , D a u v i l l i e r (1949)^ , Forbush, S t inchcoab
1 . E .B .Ber ry , and V,F, Hess , T e r r . Jlagn. A tmos .E lec t . 1 1 , 251, ( 1 9 4 2 ) .
2 . I .Lange and S.E.Forbush» Ter r .Hagn .Atmos .E lec t . 1 2 , 551, ( l j 4 2 ) .
5 . S .E .Forbuah , Phys . f iev . JO, 771 (1946 ) . 4 . A . D a a v i l l i e r , C.fi.Aced. S i r . , P a r i s , 229 .1096(1949) .
1 0 7
fl^i^ Schein (1950)5 , Hose (1950)^ and Adams (ig&O)"^.
The f i f t h cosmic- ray i n c r e a s e a s s o c i a t e d
witJa a very i n t e n s e s o l a r f l a r e was observed on 25rd
Feb. 1956. Th i s was the only case i n which o b s e r v a t i o n s
ex tended from t h e equa to r t o h i g h e r l a t i t u d e s . Th i s
s o l a r f l a r e was of impor tanee 3*, said more proiK>unc6d
i n c r e a s e s of cosmic-ray i n t e n s i t y were r e c o r d e d a t
t h i s t ime t h a n d u r i n g t h e e a r l i e r e v e n t s , i lo rsden
e t a l . (1956)® r e p o r t e d an i n c r e a s e of about 45003&
i n a n e u t r o n moni tor a t X « 57®N. Lambie and E l l i o t
(1956)^ a l s o r e p o r t e d an i n c r e a s e of about 1203t
i n a G-M coun te r a r r a y i n London. I n I n d i a , Sarabhai
e t . a l . (1956)^^ r e p o r t e d an average i n c r e a s e of 5.7?^
a t s t a t i o n s nea r t h e e q u a t o r , and on t h e b a s i s of
Burnberg and Da t tne r*8 c a l c u l a t i o n s , they s u g g e s t e d
t h a t i n c r e a s e s a t t h e s e I n d i a n s t a t i o n s were caused
by s o l a r p r o t o n s i n t h e energy range 50 to 67-5 Bev,
The c h a r a c t e r i s t i c f e a t u r e s of t h e i n c r e a s e s
du r ing t h e s e g r e a t f l a r e s can be summed up a s f o l l o w s ;
World-wide l a r g e i n c r e a s e s i n cosmic-ray i n t e n s i t y
a re very r a r e and a re a s s o c i a t e d with e x c e p t i o n a l l y
i n t e n s e s o l a r f l a r e s . The i n c r e a s e i n i n t e n s i t y p r o c e e d s very r a p i d l y , i n a few m i n u t e s , b u t t h e
5. S .E .gorbuah . T.B.St inchcomb. M.Schein«Phys.&ev.79» ' 501 ( 1 9 5 0 ) .
6 . D.C.Bose, Phys.Rev, 78, 181 ( 1 9 5 0 ) . 7 . H.Adams, P h i l Mag. i i , 505 ( 1 9 5 0 ) . t S e e append ix -2 . 8 . P.I i .Morsden, J . f f . Beery, and P . F e i l d h o u s e , J .Atoms.
T e i x P h y s . , 8 , 278 (1956) . A77 9 . M.Lambie, and H . E l l i o t , J .Atmos, T e r r . P h y 3 . ^ 1 9 5 6 ) 10 .V .Sa rabha i ,S .P .Dagga l ,H .Eazdan , and T . S . G . S ^ t r y
P r o c . I n d i a n , Acad. S c i . 509(1956) .
r a t u r n t o t h e normal l e v e l i s c o n s i d e r a b l y s lower
and t a k e s s e v e r a l liOTars. f h e maxLmuia of cosmic-rs^y
i n t e n s i t y o c c u r s about an hour a f t e r t he maximiua
of t h e v i s u a l e f f e c t . The magnitude of t h e i n c r e a s e
depends on t h e mode of d e t e c t i o n , and on l a t i t u d e ,
l o n g i t u d e and a l t i t u d e . I t i n c r e a s e s with a l t i t u d e
and l a t i t u d e , The e f f e c t i s much l a r g e r on the
n e u t r o n i n t e n s i t y t h a n on the h a r d component.
Eamert (1948)^^ , us ing a few o r b i t s of
c o a a i c - r a y p a r t i c l e s i n t e g r a t e d by Stormer (1954)
showed t h a t t h e d i s t r i b u t i o n of i n c r e a s e of Feb. 28,
1942, «aiich was observed i n i m e r i c a but no t i n
Geriaany, i n d i c a t e d l h a t p o s i t i v e p a r t i c l e s a r r i v e d
from t h e d i r e c t i o n of t h e son. S d i l u t e r (1951)^^
i n t e g r a t e d a few more o r b i t s and ^ o w e d t h a t tiiere
a r e p r e f e r r e d l o c a t i o n s of impac t s of p a r t i d e s on
the e a r t h . Such l o c a t i o n s a r e c a l l e d ^Impact Zones"-
L a t e r P i r r o r (1954)^^ , u s ing t h e o r b i t i n t e g r a t i o n s
of Stormer ( 1 9 5 4 ) ^ ^ D H i ^ t (1950)^? S c h l u t e r (1951)^^
and the r e s u l t s of the model exper iment of Malmfors
1 1 . A . l h m e r t , S . H a t u r f o r s c h . 264 ( 1 9 4 8 ) . 12 . A. S c h l u t e r , Z . H a t u r f o r s c h , 615 ( 1 9 5 1 ) . 13 . J . F i r r o r , p h y s . Eev. lOPf (1954 ) . 14 . C .S tormer , A s t r o p h y s i c s , Horv . , 1 , 1 (1934 ) . 15 . K . S w i ^ t , Ph5S.Rev. 78, 40 (1950 ) .
109
(1945)^^ and Buraberg showed t h a t t h e r e
a r e v a r i o u s Impact zoxies f o r t h e p o s i t i v e p a r t i c l e s
e m i t t e d from t h e &uu* But t h r e e of them s i t u a t e d
a t 0900 h r s . , 0400 h r s , , and 20Q0" h r s . a r e more
i m p o r t a a t t h a n the o t h e r s and the r a t i o , of t h e i n t e n -
s i t i e s i n t h e s e impact ao"nes i s 7 j 5 : 1 r e s p e c t i v e l y .
Obv ious ly , t h e 0900 h r s . , isnpact zom i s t h e most
i m p o r t a n t and i t e x t e n d s from alwut and S
geomagnet ic l e i t i t u d e to 70° geomagnet ic l a t i t u d e s .
She 0400 h r a - zoae s t r e c h e s from about 55° t o 65°N
and B geomagnetic l a t i t u d e and t h e 2000 h r s . ssone,
or t h e background impact zone* e x t e n d s from about
50° to 60°H and S geomegn. l a t i t u d e .
She above a n a l y s i s was done on t h e assumpt ion
t h a t t h e source of pspr t i c le e m i s s i o n i s a po in t o m .
But from t h e v i s u a l o b s e r v a t i o n s we know - ^ a t t h i s
i s n o t t h e ca se , f h e source h a s g o t a f i n i t e s i z e
and i t m a n i f e s t s i t s e l f i n t h e bix>:>adening of t h e
impact zones . I t i s common p r a c t i c e to take t h e
width of t h e zone a s 4 h r s .
From t h e p l o t s of f i r r o r ' s ^ ^ s i s (1954)^^
and knowing t h e geomagnetic l a t i t u d e and l o n g i t u d e .
16 . E.G.Maimfors , Arkiv . Mat. Astron» P y s i k , A52, No.8 (1945 ) .
17 . E.Burnberg» j .Geophys . Res . 272 ( 1 9 5 5 ) .
1 1 r X JL
of t h e p lace* one can e a s i l y f i n d o a t a s t o which
s t a t i o n w i l l toe i n any p a r t i c u l a r zone a t any g i v e n
t i m e . The f o l l o w i n g approximate r e l a t i o n of McNish
(1956)^® i s very coavei i ient t o conve r t from t h e
U n i v e r s a l t ime t o t h e l o c a l t i m e .
15^
^shere A i s t h e geomagnetic l o n g i t u d e of t h e
p o i n t of o b s e r v a t i o n , t deno tes u n i v e r s a l t ime ,
and 9 s t a n d s f o r l o c a l o r geomagnetic t i m e .
6 . 1 GQSMIG~RAY IHCR^ ASii.-AO! GOLEAdG (A«i24.7^S)
5?he e f f e c t of t h e s o l a r f l a r e s of impor tance
1 and 2 on cosmic- ray i n t e n s i t y i s r a t h « r l o c a l i z e d
and only a few r e p o r t s of t h e i r e f f e c t s have appeared
i n l i t e r a t u r e . P e t e r s o n and Winckler (1958)^^ , Of)
Cor r igon ( 1 9 5 8 ) ^ , Winckler a t . a l . ( l 9 5 9 ) have
r e p o r t e d cosmic- ray i n c r e a s e s a s s o c i a t e d wi th smal l
s o l a r f l a r e s . We have a l s o r e c o r d e d an i n c r e a s e i n
18 . A.C. McSish, T e r r . Magn. and Atmos. E l e c t . 4 1 * 57, ( 1956 ) .
1 9 . L . P e t e r s o n , and J . i i . f d n c i c l e r , / . P h y s . & e v . l e t t e r s i , 206 (1958) .
20. J . J . C o r r i g o n , S .F . S inger and J .Dwetn ick , Phys .Rev. l e t t e r s , i , 104 (1958) -
21. J . R . W i n c a l e r , L.H, P e t e r s o n , K . H o f f r s a n , and E .Ar ro ldy J . G e o p h y s . f i e s . ^ , 685 ( 1 9 5 9 ) .
THncon
•H
}*5° Tfitscopr
I W A ^
THCiCOPt
4
I I - ' a n lo it « /i ic MOUf?i /N a.M.T ptficenT Houmv pev^/ztncNS o/^ CUMK St, Meu^
iHTENSiry ar cmMA/rc on rrr, i f , nrtp nittr '9tf
I l l t h e i n t e n s i t y of the me son ic component a t Guimarg
( c u t o f f . r i g i d i t y 9 . 5 &ev., 2700 m. a i t . ) a s s o c i a t e d
wi th a s o l a r f l a r e of impor tance 2 on Jiine 19» 1958.
f h e r e s u l t s have been r e p o r t e d e a r l i e r , Yadav e t . a l . n n
( i960) , U n f o r t u n a t e l y our n e u t r o n moni to r was
not i n o p e r a t i o n t h a t dg^, o t h e r w i s e t h e i n f o r m a t i o n
would have been more i n t e r e s t i n g . At t h a t t ime our
two narrovy-angle t e l e s c o p e s , h a v i n g aemi -ang les 7°
and 14.5® i n t h e H.S. p l ane ana 45° each i n the E-ti
p l a n e , were a l so working i n a d d i t i o n to t h e meson
c u b i c a l t e l e s c o p e . The f l a r e was r e p o r t e d by Kodai -
k ^ a l Sojlfar o b s e r v a t o r y and i t s t a r t e d a t 0212 h r s . ,
r e a c h e d i t s maximum a t 0218 h r s . , and ended a t 0257
h r s . , &.M2. o r U . f . P u l l d e t a i l s about t h i s f l a r e
a re g i v e n i n Table 29.
The Gulmarg ( l o n g i t u d e 527^2) l o c a l t ime
co r r e spond ing to 0212 U . T , , i s 0726 h r s . which i s
i n t h e 0900 h r . zone.
Ho c o r r e c t i o n was a p p l i e d to t h e da^a and t h e
p e r c e n t d e v i a t i o n of i n t e n s i t y every hour from the
d a i l y mean has been p l o t t e d i n P i g . 55 . £>ercentage
i n c r e a s e due to the f l a r e h a s been saown i n Table 50,
22. R.S . Yadav, e t . a l . I n d i a n J .Met Geophys.11.109(1960)
112
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113
f o r the d i f f e r e a t t e l e s c o p e s , f k e d a t a eo r r e spoada
to a day b e f o r e and a day a f t e r t h e f l a r s . We see
from f i g , 35 t h a t t he i n x e n s i t y r e a c h e s a maximua
a t about 0300 h r s , B . f . whi le t h e f l a r e reac&ed i t s
peak a t 0218 h r s . U . f . I t shows t h a t cosmic-rasr
t n t e n a i t y maximiam h a s been d e l a t e d by more t h a n h a l f
an h o u r , f h i s mag^^tade of d e l ^ i s o f t h e same o r d e r
a s t h a t i n the ca se of f l a r e s of l a r g e r impor t ance .
f a r t h e r , we see t h a t t he e f f e c t i s a o r e
pronounced i n t h e case of the na r row-ang le t e l e s c o p e
{semi -ang le T®). Sefcido e t . a l . (1950)^^ a l s o found
t h a t t he e f f e c t i s l a r g e f o r nar row-angle t e l e s c o p e s ,
f h e cause of t h i s i n c r e a s e ^dith a p e r t u r e , a c c o r d i n g to
theja, i s t h a t d e t e c t o r s of v e r t i c a l n a r r o w - a n g l e s
admit p a r t i c l e s s of lower energy t h a n t h o s e with wider
a n g l e s . Eenc@,> we can conclude t h a t t h e phenomena i s
h i g h l y energy dependent , and t h e i n c r e a s e i s g r e a t e r
i n t h e lower end of t h e energy s p e c t r m .
6 . 2 ISfLPEMCE m SALL fLASES QS gaS MESOS i g f M S X f i maoRmB i f HiaHSR ammm&tiQ
I h s comparison of z ' e s u i t s f o r l a r g e and
25« X.Sek ido , M.Kod^a , ana f . X a g i , a e p . I n o s p h e r e Ees^^apan, £t 207 ( 1 9 5 0 ) .
11.4 smal l a o l a r f l a r - e s shows t h a t t he g e n e r a l f e a t u r e s
of the e o s a i c - r e y i n c r e a s e s ai'e some vtiat s i m i l a r .
Since i n c r e a s e of cosmic r ay i n t e n s i t y h a s not
been found to occur vdth e l l s o l a r f l a r e s a n a t u r a l
q u e s t i o n t h a t comes t o mind i s whether only c e r t e d n
f l a r e s produce eosmic - rays which e v e n t u a l l y r e a c h
the e a r t h , o r our o b s e r v a t i o n s a re too i n s e n s i t i v e ,
too l o c a l i z e d and a t t u n e d t o too h igh an energy t h a t
we cannot d e t e o t t h e e f f e c t i n a l l t h e c a s e s , f o
r e s o l v e t h i s , t o looic f o r small cosmic- ray
i n c r e a s e s a t t h e t ime of small s o l a r f l a r e s , f i r r o r
and otb^ers adopted a s t a t i s t i c a l approach .
Using the superimposed epoch method, f i r r o r demons-
t r a t e d t h a t f o r f l a r e s f o r which t h e o b s e r v a t i o n p o i n t
(Cliinax-48^11) was i n t h e 0900 h r , zone, t h e r e was an
i n c r e a s e o f n e a r l y i n n e u t r o n i n t e n s i t y , whi le f o r
f l a r e s i n o t h e r zones the changes i n i n t e n s i t y 9/as w i t h i n
s t a t i s t i c a l e r r o r , f h e d a t a used was c o r r e c t e d f o r
d i u r n a l e f f e c t .
S ince f i r r o r * s a n a l y s i s p e r t a i n e d to a s i n g l e
s t a t i o n and to a p e r i o d of minimum s o l a r a c t i v i t y
f o r n e u t r o n i n t e n s i t y , we cons ide red i t wor thwhi le
G o n t d . . .
15
t o ana lyze meson d a t a c o l l e c t e d durir ig the IGT
p e r i o d f o r t h r e e s t a t i o n s of d i f f e r e n t l a t i t u d e s .
So la r f l a r e d a t a used Dy u s have been t a k e n from
t h e J o u r n a l of S c i e n t i f i c and I n d u s t r i a l Eesearoh
(1958) . f h e p r e s s u r e c o r r e c t e d d a t a of a e s o n
i n t e n s i t y of h i ^ i l a t i t u d e s t a t i o n s Ottawa ( X - S ?
C h u r c h i l l ( X=70®1) and R e s o l u t e ( X was
s u p p l i e d t o u s by Dr. D .C. lose of t h e JSational Kesearch
c o u n c i l , Ot tawa 2, Canada, f h e e f f e c t of t h e diurn&l
v a r i a t i o n wqs r eaoved from the d a t a , b e f o r e p roceed ing
wi th superimposed a n a l y s i s , f h e d a t a f o r a l l the
a v a i l a b l e smal l s o l a r f l a r e d ^ s were added f o r t h e
y e a r 1958, and the averaged d a t a , o b t a i n e d t h e r e b y
were s u b j e c t e d to herTaonic a n a l y s i s . 2he d i u r n a l
v a r i a t i o n ampl i tude and phase t h u s o b t a i n e d a r e g i v e n
i n f a b l e 31. ®h® c o n t r i b u t i o n f o r d i f f e r e n t b ihoura
Was o b t a i n e d f ro® t h e r e l a t i o n .
Y^ = A s i n ( e -j- 4»)
latere I^i d i u r n a l c o n t r i b u t i o n f o r the n^^
b i h o a r , 8 assumes d i f f e r e n t v a l a o s f rom 0 to 530°
i n s t e p s of 30^ depending upon and A and <4>
axe the afiiplitu.de and ph<ase of the d i u r n a l component.
* See appendix - 3 .
r-f ifS 1 I
m
& 0 a
o o 4 (Q ^ rat] H k ^
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0 M S *
m a fiS
o o ©
4 » f - i d CM H ri ft A s
8 I T * m O o <D
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1 •
1 o •
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o
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H « i r \ CM s o
(30 rl CM
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E - < 0 n < 0
o
til
* • m H « H
i o « •H •H
S O H Hi OS f-i O +» 09
CO +» Si <S> o o
f l ie d a t a of each s t a t i o n t i ius c o r r e c t e d f o r
tJie d i u r n a l v a r i a t i o a was r e t a b l e d , c a l l i n g t a e
b ihour d u r i n g wMcli t he f lax 'e o c c u r r e d as zero
h o u r . S i m i l a r d a t a of s t a t i o n s was t hen a r r anged
a t two hour i n t e r v a l s on e i t h e r s i d e of the zero h o u r ,
The average va lue of the c o s i a i c - r a j i n t e n s i t y i s found
f o r ©ach b ihqu r i n d i v i d a a l l j and t h e n the p e r c e n t a g e
d e v i a t i o n f o r each bihoux l a c a l c u l a t e d and p l o t t e d
on a graph a g a i n s t t he co r r e spond ing b i h o u r . With
t h i s method we examined t h e e f f e c t of the smal l s o l a r
f l a r e s of impor tance 1 and 2, r e p o r t e d da r i ng t h e p e r i o d
J a n . to Aug., 1958, o n meson i n t e n s i t y r e c o r d e d a t
Ottawa ( > C h u r c h i l l •( X , and R e s o l u t e
( X 2he r e s u l t s a r e p l o t t e d i n H g . 54. f rom
the cu rves i n F ig . 34, I t i s c l e a r t h a t t he meson
i n t e n s i t y d a t a do no t shovs any i n c r e a s e i n t h e i n t e n s i t y
^hen summed up f o r f l a r e s of impor tance 2 and 1 even
t h o u ^ t h e s t a t i o n s were s i t u a t e d a t h i ^ l a t i t u d e s .
S i m i l a r a n s d y s i s was c a r r i e d ou t f o r xhe
f l a r e s of i s p o r t a n c e 2 o n l y , xhe number of such
e v e n t s i s sttie>l.ler a s seen i n s ^ p e n d i x . . 3 . . . , I h e
r e s u l t s of t h i s a n a l y s i s were p l o t t e d i n Fife. 55 .
One may say t h a t a f a l l i n i n t e n s i t y p r i o r to t h e
f l a r e o r t h e aero hoar i s g e n e r a l l y o b s e r v e d . However,
-oz
*0h *oz
- 0 - 2
O
-OZ
OTT^IV/J (f> • 57'v^
1 1
/
1 CHURCHILL (7\ ^70°/v)
e-- to 04%
Re SOLUTE ^A'SjVj
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118
t h e i n c r e a s e s of i n t e n s i t y which f o l l o w a re w i t h i n
the s t a t i s t i c a l error. Hence we do not f i n d a i ^
i n c r e a s e of mesoji i n t e n s i t y c o r r e s p o n d i n g t o s o l a r
f l a r e s of impor tance 2.
Oar r e s u l t s a r e i n agreement of wi th tiaose of
f o v a e and Lockwood (1959)^^ , S-aainer (1960)^^ and 26
Chaloupi:a e t . a l . (1960) and K-oloaieyeta and
Sergeeva
Our n e g a t i v e r e s u l t s f o r t he p e r i o d of
maximum s o l a r a c t i v i t y , compared with t h e i n c r e a s e
found by K l r r o r du r ing a p e r i o d of ainimiam s o l a r
a c t i v i t y l e a d us to t h i n k t h a t when low energy
p a r t i c l e s a re cu t o f f i n a p e r i o d of maximum s o l a r
a c t i v i t y , t h e e f f e c t of m a l l s o l a r f l a r e s
i s not s i g n i f i c a n t * I t shoi'^s t h a t -perhaps p a r t i c l e s
s e n t ou t by smal l s o l a r flggpes axe of very low energy .
24. and J.A.Lodcwoodj Phya, Rev. 113« 641(1959) . ^ ^ ^ ^
25. l . S . K a a i n e r , Srans .Xa M ( S e r . P i z . ) 1 ,92 ,148 (1960) 26. P .Ghaloupka, i i . J i r e s , and !!il.Kov9alsk.i, Caech .Phys . J
1 0 f W ( I 9 6 0 ) . 27. E.V.KolomeyetB, and G.A.Bergeeva, ^ R e s u l t s of IGl
(Moscow), Cosmic-rays No.4t152, ( I 9 6 I ) . 26. B . a . Hoka, Z .Matur fo rsch , 0 517 ( 1 9 5 0 ) . 29. l e . S . G l o k o v a j Srudy. S i i sm, 8, 53 ( 1 9 5 2 ) .
19
A p o s s i b l e r e a s o n f o r our n e g a t i v e r e s u l t
may h.owever be t h a t we feave averaged over* 2-iiour
p e r i o d s , whereas t k s d u r a t i o n of -siaall f l a r e s i s
of tiae o r d e r of iaalf an liour aad even tiie d e f i n i t e l y
obse rved peals i a F i g . 33 l a s t e d oa ly one k o u r . A
f i n e r a n a l y s i s , i f d a t a were a v a i l a b l e , m ^ snow a
p o s i t i v e r e s u l t .
CHAggSS—YII.
w m O f g H E G H A R A G f E R Q f Q Q S a i O - E A Y I B f B I S I f l y A & I A n Q i r S D q E l E f g s o l a r a b b M A a S E I g l C I)IS3!q£BAHG£a ^
A mmber of l a v e s t i g a t i o m have beea r e p o r t e d
i n l i t e r a t u r e oa. t he c h a r a c t e r of eosmic r ay i n t e n s i t y
y a r i a t i o n s dtariiig the l a r g e s o l a r f l a r e s and the
i n t e n s e magne t i c s to rms , but very l i t t l e i n f o r m a t i o n
i s a v a i l a b l e f o r v a r i a t i o n s dur ing t h e s m a l l e r s o l a r
f l a r e s , and a s s o c i a t e d magnet ic s to rms .
I n t h i s c h r ^ t e r we have d i s c u s s e d t h e e f f e c t
of 86 small s o l a r f l a r e s ( r e p o r t e d by Kodaikanal and
Sizamiah Obse rva to ry , I n d i a , du r ing J u l y , 1957 t o
August 1958) of impor tance 1 and 2 and t h e a s s o c i a t e d
m a g m t i e s torms on cosmic -ray meson i n t e n s i t y ,
r e c o r d e d a t Ottawa ( X « 5 7 ° I ) , <3hurchlll ( \ = 70°S)
and R e s o l u t e ( A d a r i n g 1957-58, by t h e 3 superimposed epoch method o f Ghree (1915) « H i ^
l a t i t u d e s t a t i o n s were chosen f o r a n a l y s i s because
i n t h i s case t h e e f f e c t i s more pronounced.
t A p a r t of t h i s i n v e s t i g a t i o n i s p u b l i s h e d i n t h e Hat . Acad. Sci ( I n d i a ) , Sec.A<1964) -
2 . J . S c i I n d u s t r . E e s . , 17A. 105 (1958) . 3 .C.Ghree , P h i l . T r a n s . Eoy. Soc . , A«212, 7 6 , ( 1 9 1 5 ) .
We kave jalso t r i e d to s tudy t h e p r o f i l e s of
i n t e a ^ t y v a r i a t i o n s , due to such magne t i c s torms t o
examine t h e . p r o p e r t i e s of c o r p u s c u l a r s t r eams and
the n a t u r e of l^aeir i n t e r a c t i o n wi th t h e e a r t h .
f h e f o l l o w i n g p o i n t s were p a r t i c u l a r l y kep t
i n view s -
(!)• The e f f e c t ' o f t hose smal l s o l a r f l a r e s , on
eosmic- ray i n t e n s i t y which a r e f o l l o w e d by m a g i ^ t i c
a t o m s and a l s o of t h o s e which a re no t f o l l o w e d by
magnet ic s t o rms .
( 2 ) . f h e e f f e c t of smal l s o l a r f l a r e s and t h e i r
a s s o c i a t e d magnet ic s torms a t d i f f e r e n t l a t i t u d e s
aad on d ^ s of d i f f e r e n t sunspot a c t i v i t y .
( 5 ) . The e f f e c t of s o l a r f l a r e s of d i f f e r e n t
impor tance on c o ^ i c r ay i n t e n s i t y .
( 4 ) . A s s o c i a t i o n between t h e s o l a r phenomena
and subsequent geomagnetic e f f e c t s , which a re
s t u d i e d by c o n s i d e r i n g t h e v a l u e s o f t h e geomagnetic
i n d i c e s G^.
The d a t a of geomagnet ic s torms and C^ v a l u e s
u s e d h e r e a r e tsifcen f rom J .Geophya. Ees , 1957
and 1958, For 1958, t h e v a l u e s of G^ a r e t a k e n
122
from t h e d a t a s u p p l i e d by Br. J . B a r t l e a , Zuricli
O b s e r v a t o r y , Swit izer laad.
7 . 1 ffiSfHQD OF AMALXSIS
fi^e 4 a i l j average c o a a i c - r a y meson i n t e n s i t y
was c a l c u l a t e d f o r each of t h e seven days b e f o r e t h e
f l a r e and seven days a f t e r i t . The average of t h e
14 days tfiOcen t o g e t h e r was t h e n compeared v?ith t h e
d a i l y aicerage and p e r c e n t a g e d e v i a t i o n s c a l c u l a t e d .
7 . 2 ASSQClAaiOI BEi'VilEEH MB DAILY MEAS MBaOH ISfEMSl!!!! ASP SOLAR fLAE£S gOLLOV EB ASD 502 fOLLQWEB BX ffiA&H£fIC>SfgiiaS s
The meson i n t e n s i t y a t Ottavtfa i s examined
from t h e p o i n t of view as d i s c u s s e d below
E i ^ t y s i x f l a r e s obse rved d u r i n g 1957-58
a r e d i v i d e d i n t o two ^ o u p s A and B. Group A
c o n t a i n s t h o s e f l a r e s which a r e fo l l owed by Magne t ic
s to rms .
I f t h e i n t e r v a l , A t , between t h e o c c u r r e n c e o f
s o l a r f l a r e s and t h e geomagnetic s to rms i s l e s s t h a n
5 d ^ s , t h e n t h e f l a r e i s c o n s i d e r e d t o be f o l l o w e d
by a magne t ic s torm, and i s pu t i n group A. I f t h e
de lay i s greatJ^^han 5 days , t h e f l a r e i s c o n s i d e r e d
23
t o be no t f o l l o w e d by a m a g n e t i c s torm and i s p u t
i n groap B. I n t h i s way 76 f l a r e s f a l l i n group A
and 10 f a l l i n group B.
Tke r e s u l t s o b t a i n e d a r e shown i n f i g . 36 .
f h e curve f o r t h e f l a r e s f o l l o w e d by m a g n e t i c s t o r m s
shows t h e p e c t i l i a r f e a t u r e t h a t t h e average meson
i n t e n s i t y i n c r e a s e s even b e f o r e t h e f l a r e day . She
maximm i n c r e a s e i s about 0 . 1 7 i 0 . 0 3 6 ^ and i t o c c u r s
abou t two days b e f o r e t h e f l a r e . A f t e r t h e f l a r e ,
t h e i n t e n s i t y f a l l s below i t s ave rage v a l u e . I t
c o n t i n u e s t o f a l l u n t i l t h e minimum i s r e a c h e d two
t o t h r e e days a f t e r t h e f l a r e . She minimum i s abou t
- 0 . 2 4 • 0.056?&.
I n t h e ease o f t h e f l a r e s which a r e n o t
f o l l o w e d by m a g n e t i c s t o r m s , t h e meson i n t e n s i t y
shows a t r e n d t h a t i s so to s a y , i n phase o p p o s i t i o n
t o t h e e a r l i e r c a s e . Average i n t e n s i t y r e a d i e s a
minimum of abou t ~ 0 . 8 1 ± 0 . 0 4 ^ n e a r l y two days b e f o r e
t h e f l a r e . I t r e t u r n s t o i t s normal v a l u e and i n c r e a s e s
to about 4-0.37 i 0 . 0 4 ^ two t o t h r e e days a f t e r t h e
f l a r e .
Our r e s u l t s a r e i n g e n e r a l agreement w i t h
t h o s e of Hogg (1949)^ who bas^d h i s o b s e r v a t i o n s
4 . A.E.Eogg, Memoirs o f t h e common w e a l t h o b s e r v a t o r y Canbe r ra , No.10 ( 1 9 4 9 ) .
/ye.Si //j-^/p/re^ sv/'d-iffotcf> VTLuei of ^off
7 u / t , - s B f ^ w e / 7 / f o / f ^ r e ^ j r F i / 7 / r e i ^ h k m
>t/tt ^^iioivro />/ro A^oT ftttoh/eo
124
on l a r g e s o l a r f l a r e s ,
7 .5 VARlAglOH Qi' COSMIC RAI MESQH WI H SOLAR FLAilES {IX)LLQW£I) BY MAGF^flC SfOfiM) DlfFE&SIf LAglTPJDDS.
On t h e b a s i s of 41 f l a r e s , f i g . 57 and Sab le
52 h a s been c o n s t r u c t e d .
f rom f i g . 57» i t i s no ted t h a t meson i n t e n s i t y
does z ^ t show ax^ s i g n i f i c a n t i n c r e a s e on t h e f l a r e
d ^ du r ing t h e p e r i o d exeaained h e r e a t any l a t i t u d e .
I t means t h a t du r ing t h e p e r i o d J a n . t o Aug. 1958
(which i s t h e p e r i o d of maximum sunspot a c t i v i t y )
meson i n t e n s i t y does no t show aiiy i n c r e a s e a a s o c i a t e d
wi th ®aall sol^tr f l a r e s of impor tance 1 and 2, a t
any l a t i t u d e .
Kaminer (1960)^ , Towle and Lockwood (1959)^
and S h i e l m e t t e e t . a l . (1960J a l s o a r r i v e d a t t h e
same r e s u l t .
5. H.S. Kaminer, SJrans. Ya FAN, 92 & 148(1960)} P r o c . lOI'AP, Moscow Gonf. ( 1959 ) , V o l . 4 , 42 o r 44.
6 . L . C . f o w l e , and J.A.Iiockwood, Phys . Sev. 115. 691 , ® ( 1 9 5 9 ) .
7 . B . G h i e l m e t t e , J .U.Anderson , J . E . Cardoso, &. fflanaano, J . ( J . E o e d e r e r , J . a . and R. Santochor Huovo. Cimento, 1^ , 87 (1960) .
1-0/iYS B£ro/ig /9HO THf F l f t m 0/9y.
125
57 a l s o shows t h a t a f t e r t he f l a r e day,
mesoa i n t e n s i t y d e c r e a s e s below t h e normal l e v e l ,
rea<aaes the minimiaa and t h e n s lowly r e c o v e r s i t s
normal l e v e l , ®his i s n o t i c e d a t a l l t h e t h r e e
l a t i t u d e s examined h e r e . The magnitude of the dip
(maxiBraffi dec rease ) and i t s t ime of occi i r rence a t
d i f f e r e n t l a t i t u d e s a re g iven i n f a b l e 32. From
t h e r e s u l t s g i v e n i n f a b l e 32, i t i s e v i d e n t t h a t
t h e magnitude of t h e d ip i s a lmost c o n s t a n t on a l l
t h e t h r e e l a t i t u d e s from 5?° t o 83®H. But t h e t ime
of o c c u r r e n c e of t h e d ip i n c r e a s e s a s t h e l a t i t u d e
i n c r e a s e s . She d ip becomes more and more sha l low
a s we move towards t h e p o l e , f h i s i n d i c a t e s t h a t
the p r o f i l e of t h e dip and i t s t ime of occu r r ence
a r e r i ^ d i t y dependent . Webber (1962)^ a l s o d i s e u s s e d
cosmic-ray d e c r e a s e s a s s o c i a t e d with l a r g e magne t i c
s torms and showed a very pronounced r i g i d i t y dependence
e x t e n d i n g a t l e a s t over t h e r ange 1 - 3 0 Gev.
Another s ign i f i cgya t p o i n t from t h e s e cu rves i s
t h a t t h e r e i s an i n c r e a s e i n meson i n t e n s i t y b e f o r e
the f l a r e d ^ on a l l t h e l a t i t u d e s examined h e r e , f h i s
i n c r e a s e occu r s on t h e f i r s t ds^ b e f o r e t h e f l a r e day
8 . » .H. \ n " W I?")-
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CO 0 54
on fie s o l u t e (83*^5) and Ciii ircii i l l (75®ir), whi le a t
Ot tawa i t o c c u r s on 2nd day be fo re the f l a r e
day.
7 . 4 ASSQCIAflOH B£fW££H yAHlA2I0HS Of M£SQM IITEHSIgr AND TES: XMPQ&fANGB Qg fH£ SOLAR F L ^ S S .
76 f l a r e s wMeh were f o l l o w e d by magnet ic
s torms i n tvso groups «e re s t u d i e d t o see t h e a s s o -
c i a t i o n between t h e impor tance o f t h e f l a r e s and t h e
<Siaraeter of t he cosmic r a y i n t e n s i t y v a r i a t i o n s , f h e
f i r s t group h a s 12 f l a r e s of impor tance 2, and t h e
second group c o n t a i n s 64 f l a r e s of i m p o r t ^ c e I t
obse rved d u r i n g t h e y e a r 1957-58 . f h e r e s u l t s a r e
shown i n F i g . 58 and Sab le 55. I t i s aeen t h a t t h e r e
i s no i n c r e a s e of meson i n t e n s i t y on t h e f l a r e day jNfo r
any dgy j u s t a f t e r t h e f l a r e djsy.
f h e r e s i s t s , which a r e based on a s l i ^ t l y
d i f f e r e n t s t u d y , a re i n agreement with t h o s e d i s c u s s e d
i n t h e c h a p t e r and a l s o wi th t h e o t h e r i n v e s t i -
g a t o r s .
f h e s i g n i f i c a n t p o i n t s i n t h e c h a r a c t e r of
meson i n t e n s i t y v a r i a t i o n s shown i n f i g . 58 a re as
f o l l o w s s -
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(1) Both i n tiie case of the f l a r e s of impor tance
2 and 1 , meson i n t e n s i t y siiows a s i g n i f i c a n t dec r ea se
on 2nd day a f t e r the f l a r e day. f k e magni tude of t h e
dec rease ( d i p ) f o r f l a r e s of impor tance 2 i s - l .S+O.OSS^
and i t o c c u r s on the second day f o l l o w i n g t h e f l a r e .
Bor f l a r e s of Importance 1» the magni tude of t h e d e c r e a s e
i s - 0 . 5 2 ± 0 .037^ and i t o c c u r s on t h e second day
a f t e r t he f l a r e ,
(2 ) Both i n t h e case of t h e f l a r e s of impor tance
2 and 1 , meson i n t e n s i t y shows a s i @ 3 l f i c a n t i n c r e a s e
on the 2nd day p r i o r t o t h e f l a r e and we c a l l t h i s
i n c r e a s e ^ ' P r e - f l a r e i n c r e a s e " . The magni tude of t h e s e
p r e - f l a r e i n c r e a s e s f o r t h e f l a r e s of impor tance 2 and
1 a r e -1-1.35 + 0 .085^ and "I-0.75 0 .057^ r e s p e c t i v e l y .
(3) During t h e p e r i o d J u l y 1957 to August 1958,
\i!^ich i s t h e p e r i o d of m i simum s o l a r a c t i v i t y , i t i s
found t h a t t h e magni tude of t h e dec rease of meson
i n t e n s i t y a f t e r t he f l a r e day a s we l l as the p r e - f l a r e
i n c r e a s e i s l a r g e r i n t h e case of t h e f l a r e s of
impor tance 2 t h a n i n t h e case of t h e f l a r e s of
impor tance But t h e t ime of occu r r ence of the
maximum d e c r e a s e s ( d i p ) and maximum p r e - f l a r e i n c r e a s e
i s t he same f o r t h e f l a r e s of impor tance 2 as of
impor tance 1 .
7 . 3 aBLA!PlQlSHlP BBgWESa m S ?ARIA£I0IS Qg MjESOI IMfSHSIfl AMD SHE ^OSSfOi' ACf l¥ I$ I .
f o obse rve t h e e f f e c t of s o l ^ f l a r e s ( c o n s i -
dered oa ly t h o s e f o l l o w e d by magne t ic s torms) of
l e s s e r impor tance on meson i n t e n s i t y d u r i n g t h e
t ime of d i f f e r e n t sunspot a c t i v i t y , t h e p e r i o d
1957-58 h a s t>een d iv ided i n t o t h r e e g roups . On t h e
b a s i s o f t h e sui i -spot iHambers.
( i ) f h e f i r s t group e x t e n d s from J u l y to
Beceaber 1957.
( i i ) The second group (which i s t he sum of
the f i r s t end second) ex t ends f rom J u l y
1957 t o August , 1958 and
( i i i ) The t h i r d group from January to August ,
1958.
Daily mean meson i n t e n s i t y of Ottawa h a s been
ana lysed f o r t h e s e t h r e e groups and the r e s u l t s o b t a i n e d
are* g i v e n i n 2ab l e 54, and p l o t t e d i n f i g . 59 .
f h e s i g n i f i c a n t p o i n t s i n t h e c h a r a c t e r of
meson i n t e n s i t y v a r i a t i o n s shown i n 2'ig. 39 a r e
a s f o l l o w s s -
( i ) Form t h e t a b l e 34 and F ig . 59, i t i s c l e a r
t h a t f o r a l l t h e t h r e e ^ o u p s d i s c u s s e d above, t h e r e
, C'T'Jt^x. fS/
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132
i s a d ip wMcb o c c u r s between two o r t h r e e days a f t e r
the f l a r e day. The magni tudes of t h i s d ip f o r t h e
f i r s t , second and t h i r d group a r e , - 1 . 0 4 t 0 , 0 4 4 ^ ,
- 0 . 5 7 t 0 .034^ and - 0 . 2 ? + 0 . 0 4 6 ^ r e s p e c t i v e l y . Th i s
shows t h a t t h e magnitude o f t h e dec rease ( d i p ) of a e s o a
i n t e n s i t y i n c r e a s e s a s the sunspot a c t i v i t y i n c r e a s e s ,
bu t i t s t ime of occur rence i s a lmost c o n s t a n t d u r i n g
t h e p e r i o d of d i f f e r e n t sunspot a c t i v i t i e s .
( i i ) Por al.l t h e t h r e e grouj js , meson i n t e n s i t y
shows a s i g n i f i c a n t i n c r e a s e ( p r e - f l a r e , i n c r e a s e )
on t h e 2nd day p r i o r to t h e f l a r e day. Ihe magiiitmdes
of t h i s i n c r e a s e f o r t h e t h r e e groups a re 1 . 4 2 + 0.004?^
1 .19 t O . O 3 0 t and 0 .49 ± 0 .04^^ r e s p e c t i v e l y , from
t h e s e r e s u l t s one may say t h a t t h e magnitude of the
p r e - f l a r e i n c r e a s e a l s o i n c r e a s e s a s t h e sunspot
a c t i v i t y i n c r e a s e s .
7 . 6 a£IiA!P10HSIiIg BBgtfBEII aiflALL SQLA£ FLMES M B GBOMAaS iPIC BiSlD£BA10£5.
!Eh@ r e l a t i o n between smal l s o l a r f l a r e s and
the geomegnetic e f f e c t s i s s t u d i e d by the fihre®
method, c o n s i d e r i n g t h e geomagnetic i n d i c e s C^ f o r
t h e da^rg b e f o r e and a f t e r t h e f l a r e e v e n t s , f h e
r e l a t i o n betv/een G and f l a r e s of impor tance 2 ( n i n e
cases ) and of impor tance 1 (57 cases) a re examined
33
s e p a r a t e l y f o r the pe r iod J a n . to Aug., 1958 and
the r e s u l t s a re shown i n f i g . 40.
I n the case of t he f l a r e s of importance 2,
the average superlmpoaed v a l u e s ( i n of C show i r
a l a r g e i n c r e a s e {s tar t ing from the f i r s t da^ a f t e r t h e
f l a r e and r e a c h i n g the peak value on the 2nd da^
a f t e r t he f l a r e . I n the case of the f l a r e s of impor -
t ance 1 , the average superimposed va lue of ( i n fo)
s t a r t s i n c r e a s i n g on the f l a r e d ^ and shows a peak
value on the f i r s t ds^ a f t e r the f l a r e ,
She magnitude of i n c r e a s e f o r t he peak va lue
of G^ i s q u i t e l a r g e i n the case of t h e f l a r e s of
impor tance 2 . 3!he delg^ i s a l so l a r g e r i n t h e former
case t h a n i n the l a t t e r . Since t h e former i s based
only on 9 c a s e s , t h e s e c o n c l u s i o n s a r e only of a
t e n t a t i v e n a t u r e . However, i t i s c e r t a i n t h a t t h e r e i s
an i n c r e a s e i n C^ a f t e r s o l a r f l a r e s .
Similar r e l a t i o n was a l so observed by Dodson
and Hedeman (1958)^considering the solar f l a r e s of a l l
importances during the period J a n . 1949 to Apri l ,
1956 (115 e a s e s ) , and by Denisse (1952)^^ and Simon
(1954)^^ .
9 . H.M.Iiodson, and JS.&.Hedaman, ^ J.G-eophys., Res .65 . e 77 (1958) .
1 0 . J . f . D ^ n i s e e , Ann. Geophys., 8 , 55. (1962) . 11. J . f . i i m o n , P h y s . , Hev. , l i , ~ 4 4 7 (1954) .
c./
\ /
^ "iOLtf" A i. ft hi i / /Mf-Of^l / \ f y c 'Of u i '
/ \
\ / \ V
1 I V
1 _J 1 1 1 1 1——1
( J7 C^J/I^
FKi AO /tei/tr/on aeTi%ff£/v T//e soLaa f^iiv^e />/ro
oeoM/7o^i£r/c D/iTL/f/O'^^css U) ca/fvfs li-B tme /fei/irioM Bem££M Sl/P£/!P<>ieD k'Ml/^S Of^ Cp /IMO SOL/V/t ft^^e o^
34
7 . 7 fME BBLAl BETWEEE mM QCC0a&£HQl 0? A SOLAR FhARE. ABB TEB STA&f Of TH£- ASSOCIATE]) MMBBglO SSORMS .
S t a t i s t i c a l d a t a t o s tudy t h e e f f e c t i s g i v e n
i n l iable 35 . The average de lay i a oux ease i s one
day and 5 Hours,, The f r e q u e n c y d i s t r i b u t i o n i s
shown i n F i g . 41 . I n Table 35, the delay )
i s c a l c u l a t e d i n u n i t s of a whole day ( d i f f e r e n c e o n
c a l e n d e r d a t e s ) r a t h e r t h a n i n t h e e x a c t t i m e
i n t e r v a l i n hocira between t h e s t a r t of f l a r e s and
stoffiBs.
7 . 8 msCUSSIOS AMB lMT£RPRE*gATI01 QW .ElPSRIMBMrAI, EESULg J -
The d e c r e a s e of meson i n t e n s i t y f o l l o w i n g
f l a r e s w i t h magne t i c s to rms shows a s s o c i a t i o n be tween
magne t i c s to rms and cosmic r a y d e c r e a s e , f h i s
i n d i c a t e s t h a t b o t h have a coiamon c a u s e . I n t h e p a s t
y e a r s many modesls have been p roposed t o e x p l a i n t h e
cause of t h e s e Porbush type cosmic - r ay d e c r e a s e s ,
12 Chapffijm (1937) s u g g e s t e d t h a t t h e s e may be
e x p l a i n e d on the b a s i s of a r i n g - c u r r e n t of t h e
12 . S.Ghapman, S a t u r e , 140, 423 ( 1 9 3 7 ) .
' I
r/c. oarfftaurtof* cs-rt^eet^
At ^SCL/ift At pc^'H'ii^f^rs 7He //vrsMi rfI. ah: rn.een
THe 4-^/c ^ o.'-- oea/^^a^rr/c S70fi!M.
135
^ ^ ^ ^ ^ <M r^
to 0 m o
O
a> %
«H <H U O
a r-l g o
in
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t<A 8 3 ^ try (<\
•P rt O r4 to
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oo c-
0}
5
136
p o s t u l a t e d toy Chapman and F e r r a r o i n t l i e i r t h e o r y 1
of m a g n e t i c s t o n n s . Hagaahiaa ( 1 9 5 1 ) , (1955)
m o d i f i e d t h i s r i n g c u r r e n t h y p o t h e s i s . But t h i s r i n g
c u r r e n t h y p o t h e s i s o r any change i n t h e e a r t h ' s d i p o l e
f i e l d cannot e x p l a i n c o s a a i c - r ^ d e c r e a s e s o b s e r v e d
« 3 a t p o l a r l a t i t u d e s , C h u r c h i l l (70^!f) and R e s o l u t e
d u r i n g vhe p e r i o d 1957-58 ( p e r i o d of maximum
s o l a r a c t i v i t y ) and a l s o c o s m i c - r a y d e c r e a s e s o b s e r v e d
a t ' Ihule i n 1951. 'Ihus t h e r i n g c u r r e n t
i j y p o t h e s i s f o r coacaic r a y d e c r e a s e s i s u n t e n a b l e .
M o r r i s o n (1956)^^ e x p l a i n e d t h e c o s m i c - r a y
d e c r e a s e s on. t h e b a s i s of t h e d i f f a s i o n a o d e l . M o r r i s o n ' a
model h a s been ex tended by b a r k e r (1956)^^ and a l s o
by S inge r ( 1 9 5 7 ) ^ ^ . But one d i f f i c u l t y wi th t h i s
model i s t h a t i t r e q u i r e s l a r g e m a g n e t i c f i e l d s t o
a f f e c t c o s m i c - r a y s of r e l e v a n t e n e r g i e s , ( a b o u t 30
G e v . ) . Another d i f f i c u l t y i s t h a t i t l e a d s t o l a r g e
l a t i t u d e dependence of t h e cosmic - r ay d e c r e a s e s . On
t h e c o n t r a r y , t h e o b s e r v e d l a t i t u d e e f f e c t i s v e r y
smal l and t h e v a r i a t i o n s obse rved i n n e u t r o n c o u n t e r s
a r e not very much g r e a t e r t h a n t h o s e of i o n chambers
o r mea>n t e l e s c o p e s a t s e a l e v e l . 5?his d i f f u s i o n
15 . K . l a g a s h i m a , J .^eomag and ( j -eoe lec t .^ j lOOClgSl ) , J .Geomag. and G e o e l e c t . ^ , 1 4 1 ( 1 9 5 3 ,
1 4 . P . M o r r i s o n , P b y s . & e v . a ^ , 1 3 9 7 ( 1 9 5 6 ) . 15 . S . l .ParjEer, Phys .Eev . lQS , 1518(1956) j l l O j 1445(1958) . 16 . S . F . S i n g e r , Huovo e imento , S u p p l . l l , ( 1 9 5 7 ) $ S ,
Ser 1 ^ , 3 2 6 , 2 3 4 ( 1 9 5 8 ) .
3330del a l s o doee not account f o r t h e i n c r e a s e i n
i n t e n s i t y observed us b e f o r e t h e f l a r e s .
Al fven <194^, 1949)^'^ and Ifagashima (1951,1953)^®
proposed tke e l e c t r i c f i e l d model based on t h e s o l a r
streaBJ. M f v e n sugges ted t h a t t h e dec r ea se i n cosmic-
r ^ i n t e n s i t y i s due t o t h e e l e c t r i c f i e l d «h ich a r i s e s
a s a r e s u l t of the mot ion of t h e s o l a r a o r p u s o u l a r
s t ream through, t h e s o l a r magne t i c f i e l d . According
to t h i s model, t he energy l o s t by a p a r t i c l e c r o s s i n g
the s o l a r s t ream i s ( ¥ M ) b , where V i s t h e s t r e a a
v e l o c i t y , H i s t h e ' F r o z e n - i n " magne t ic f i e l d c a r r i e d
hy t h e s t r e o a , and b i s t h e b r e a d t h of t h e s t r eam.
I 'h i s model h a s been extended by Barnberg and D a t t n e r
(1954)^^ .
This ffiodel ^ s o e x p l a i n s t h e i n c r e a s e s i n
®es©a i n t e n s i t y found by ua t o occur b e f o r e t h e
f l a r e day. Blokh, Glokova and Borman (1959)^^a l so
obse rved smal l i n c r e a s e s i n t h e case of t h e 21.
i n d i v i d u a l magne t ic s to rms . Dorman ( I960) and 22 o t h e r s e x p r e s s e d t h e o p i n i o n t h a t t h i s i n c r e a s e
17. H . l l f v e a , l a t u r e , 1S8^618{1946) ;gh5ra .aev.72 1752(1949) .
18 . K.fifagashima, J .Geomg.Geoelec t . , ^ 1 0 0 ( 1 9 5 0 ) | 1 , 1 4 1 ( 1 9 5 5 ) .
19 . B.A.Burnberg and A . D a t t n e r . , M e l i u s , 6 , 7 5 $ 2 5 4 ( 1 9 5 4 ) . 20. Blokh, Slokova, and Dorman ,C .S .Var i a t i ons .
Underground, s e a - l e v e l and i n S t r a t o s p h e r e , (Moscow),! , ( 1 9 5 9 ) .
21 . L.I.I)®rman,Broc.Moscow Cosmic-ray CJonference V o l . 4 , ( I 9 6 0 ) .
22. P r o c e e d i n g s of t h e Moscow Oosmie-ray c o n f e r e n c e , Vo l .4 , ( I 9 6 0 ) .
i s due to a siiocis: wave from tJie a b r u p t l y approacii i i ig
f a c e of t h e c o r p u s c u l a r beam c a r r y i n g a f r o z e a - l J i
magae t i c f i e l d , f k e p o s s i M l i t y of t h e f o r m a t i o n
of a shock wave by means of tiie f r o n t f a c e ( o r tia©
appro aching f a c e ) of t h e beam ( o r stream) was d i s -
cussed by Singer (1957)^^ who a l so i n v e s t i g a t e d t h e
geomagnetic e f f e c t s of t h i s shock wave on i t s a r r i v a l
a t the e a r t h . H e c e n t l y , t h e a c c e l e r a t i o n of charged
p a r t i c l e s d u r i n g the passage of t h e f r o n t of a shock
wave i n magne t i c plasma has been c o n s i d e r e d i n d e t a i l
by Dorman and F r e i d a a n ( 1 9 5 9 ) a n d Dorman (1960)^^
and Snabaasky (1961)^^ . I t i s shown t h a t i n t h e f r o n t
p a r t of a s o l a r s t ream c a r r y i n g a F r o s e n - i n magne t i c
f i e l d , t h e plasma and the magnet ic f i e l d a r e a p p a r e n t l y
compressed. Hence t h i s eahaaced magnet ic f i e l d w i l l
r e f l e c t t h e chai'ged p a r t i c l e s i n c i d y n t on i t , and
among a l l t he p a r t i c l e s f a l l i n g on t h e s u r f a c e of t h e
e a r t h t h e r e w i l l be a d e f i n i t e f r a c t i o n of t h o s e
23. L . I . Dorman and &. I . Freioman, Problems of Magneto hydro ' dynamics, and plasma
P h y s i c s ( E i g a ) , 77, ( 1 9 5 9 ) . 24. L . I . Dorman, Eoscow, O.K. Gonference , ? o l . 4 ,
132 or 134(1960) . 25. Y.P.Shabansky, 2h. Cksp. t&or , P i a . ^ , 1 1 0 7 ( 1 3 6 1 ) .
p a r t i c l e s t k a t a r e r e f l e c t e d f rom t h e s t r eam.
I n sueh r e f l e c t i o n t h e r e i s a head-on c o l i i s i o m
i n which p a r t i c l e energy inore&aes soate¥?n.at, aad
t h i s should l e a d to an i n c r e a s e In t h e i n t e n s i t y
of cosff l ic-rays on t h e s u r f a c e of t h e e a r t h ,
( i i ) l-iatur® of the p r o f i l e s and the s o l a r s t r e a m .
f h e r e s u l t s d i s c u s s e d i n t h i s c h ^ t e r have
shown t h a t i n thejcase of the f l a r e s f o l l o w e d by
magne t ic s to rms t h e r e i s an i n c r e a s e i n cosmic- ray
s e s o n i n t e n s i t y b e f o r e t h e f l a r e on t h e 2nd day.
ThtB i n c r e a s e i s a l s o n o t i c e d i n t h e case of f l a r e s
of impor tance 2 and 1 and a t d i f f e r e n t l a t i t u d e s ,
f rom t h e o r e t i c a l c o n s i d e r a t i o n developed oy i^riaan
and o t h e r i n v e s t i g a t o r s , i t i s c l e a r t h a t t h i s
i n c r e a s e could occiir on ly i n t h e case of magne t ic
s to rms v^ ich g ive r i s e t o t y p e s I aad I I f a l l i n g p r o f i l e s
( f i g . 42) and the i n c r e a s e should not occtir wi th s t o n a s
of type n i p r o f i l e s (Borman I960) .
f h u s , on a p u r e l y q u a l i t a t i v e o a s i s we can
"broadly s&y t h a t the dec rease p r o f i l e m i c h ise-
obse rved i n i?ig. 36, f o r t he f l a r e s f o l l o w e d by
magne t ic s torms i s e i t h e r of t y p e I or t ype I I , P i g . 4 2 .
Froai f i g . 36 i t seems t h a t t h e dec rease p r o f i l e i s
of t h e t ype I I . i^om t h e curvos i n J±g* which
"TIMt D/F/lRtNl /POSSIBLE 7 ypfs O/^ /'/VOr/Li3 Cf/ C OSMJC .^ y/Y /A/y/TA/S/r y i^/9/e//9r/0/VS
g i v e t}ie|decreasQ p r o f i l e of meson i n t e n s i t y a t
t i i ree d i f f s r e a t l a t i t u d e s , i t seems t k a t i a t h i s
case a l s o the a©crease p r o f i l e s on d i f f e r e n t
l a t i t u d e s a re of t j p e I I . F i g s . 38 and show
t h a t f o r f l a r t ' s of impor tance 2 and 1 and a l ao f o r
f l a r e s aurin^^ feie p e r i o d e f d i f f e r e n t sanspo t
a c t i v i t j , the dec rease p r o f i l e i s of tne type I I .
Ihtts on t h e b a s i s of t h e s e p r o f i l e s , one s a y say
t h a t t h e s e meson i n t e n s i t y d e c r e a s e s eo^e caused
when t h e e a r t h i s enveloped hy t h e I q a d i n g f a c e
of the s t r eam,
( i i i ) SJEGREASS at hL^hm LAI'IIUB^S
i ' i g . 37» shows t h a t t h e p o l a r d e c r e a s e s
seeass t o he both l a r g e r aad wider t h a n t h o s e a t o t h e r
l a t i t u d e s . The r e a s o n f o r t h i s (&& d i s c u s s e d by S inger
.1958} may t h e p resence of t r a j e c t o r y d i s p e r s i o n
v^hich e x i s t s a t a l l o t h e r l a t i t u d e s . " But a t the p o l a r
l a t i t u d e s even a aon-momchrojaate d e t e c t o r ? , l l i
r e c e i v e d a l l primary p a r t i c l e s from t h e ssme d i r e c t i o n .
S inger h e l d thu-t ^he mot ion of the p a r t i c l e s beyond
about 40-eaa : ' th - radi i hecoises c o n t r o l l e d by the i n t e r -
p l a n e t a r y magne t i c f i e l d . I n any c a s e , whatever t h e
cause of t h e fo rbush d e c r e a s e s i t c l e a r l y a f f e c t s a l l
t h e p a r t i c l e s e n t e r i n g t h e pola?^ a e t e c t o r , bu t oa ly
14
a p o r t i o n of t h e p a r t i c l e s a t o t h e r l a t i t u d e s .
T h i s f a c t i n d i c a t e s t h a t t h e p o l a r t e l e s c o p e h a s
the i m p o r t a n t a b i l i t y to look ou t f u r t h e r i n t o
space t h a n t e l e s c o p e s a t o t h e r l a t i t u d e s .
APPBHDIX
f h e u n c o r r e c t e d d a t a of meson i n t e n s i t y f o r
t h e month of November 1958, r e c o r d e d a t Siilmarg
( 24.7®I) i s g iven i n f a b l e 57. f h i s d a t a i s t o
be c o r r e c t e d f o r ba rome te r i c p r e s s u r e u s i n g t h e
f o l l o w i n g e q u a t i o n .
l ^ e r e
I p » b i h o u r l y meson i n t e n s i t y c o r r e c t e d
f o r b a r o m e t e r i c p r e s s u r e .
= Uncor rec t ed bifeourly meson i n t e n s i t y .
B a 2he p r e s s u r e c o e f f i c i e n t .
? a Bihour ly v a l u e s f o r p r e s s u r e .
P a Monthly mean v a l u e s of p r e s s u r e , v^ ich
i s 39*7 iBb. i n t h i s e a s e .
( i ) g^SSOAii; OUiiEilQailQH J -
froai t a b l e 57 and 58 t h e v a l u e s of I^ .and
( 1 - f ) , f o r t h e f i r s t day and 0000 h o u r s , a r e 6 5 7 . 5
and +2 .4 r e s p e c t i v e l y . S u b s t i t u t i n g t h e above v a l u e s
l a ( A . l ) , we g e t
• 657 .5 - 1 . 1 8 ( 2 . 4 ) P I p « 657 .5 - 2 .85 « 654.67
o r 1 ^ ^ 6 5 4 , 7 count a / b i - h o u r .
t he p r e s s u r e c o r r e c t e d va lue f o r t h e f i r s t
day and 0000 h r . eomes ou t t o be = 654*7 O o i m t s / b l - h o u r .
Data i s c o r r e c t e d f o r each d a / and each b i h o u r . Thoee
r e s m l t s a re presteated i n f a b l e 36.
I r o a t h i s p r e s s u r e o o r r e c t e d d a t a , g iven i n
f a b l e 36, t n e 1 2 - b i h o u r l y average v a l u e s a r e o b t a i n e d
by a v e r a g i n g the 12 v e r t i c a l columns, f h e s e v a l u e s
a r e g iven a t t h e bottom of Sable 36 . 0 s i n g t h e s e
1 2 - b i - h o u r l y v a l u e s the d a t a f o r t h i s month can be
harmojaical ly ana lysed to ge t t h e f i r s t and second
harmonic components of t h e d a i l y v a r i a t i o n of meson
i n t e n s i t y . The method i s d i s c u s s e d below i -
( i i ) aAEMOaiQ AliU iYSIS s -
f a b l e 39, g i v e s t h e s imple r method of
harmonic a n i ^ y s i s i n t h e Tabular fo rm, u^ , u ^ , Ug ,
. . . . . . . . u ^ ^ a r e t h e 1 2 - b i h o u r l y v a l u e s , f h e a c t u a l
v a l u e s of , ^ ^ ^ ^ ^ fJtom f a b l e 36 ,
a r e s u b s t i t u t e d i n Table 39 a t t h e i r p rope r p l a c e s
a s shown i n t a b l e 40.
f h a s from f a b l e 40 , t h e affl-plitude and phase
o f t h e f i r s t hax^moaic component f o r Ifov. 1958, comes
o u t t o be and 11^ r e s p e c t i v e l y . S i m i l a r l y one
eaa gfet ti ie ampl i tude and phase of t h e second haraoiaic
compoaerit a l so f r o a t k i s t a b l e 40 .
iri!
vo ers t I
m H *
<4 oa o ^ a
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APgMDIX
A e t a a l i y e r a p t i o n s on t h e chromosphere of
t h e sun a r e termed a s «Sola r f l a r e s « . A s o l a r
f l a r e i s a r e g i o n i n t h e chroaosphere hav ing p r o -
j e c t e d a r e a of a few hundred m i l l i o n t h s of t h e
v i s i b l e diak, of the aim, whieh e m i t s i i^^ht i n t h e
Hydrogen and a t l i e r p a r t s of t h e spectruia s d t h
g r e a t e r i n t e n s i t y t h a n the con t inuous background
of t h e s o l a r d i s k , f l a r e s u s u a l l y s t a r t sudden ly ,
r e a c h maximuffi i n t e n s i t y i n a few si inutes» and
d i s a p p e a r w i t h i n an h o u r , f h e r e p o r t s on f l a r e s
normal ly g i v e t imes of beg inn ing , maximiaffl and t h e
end of f l a r e , t h e p o s i t i o n , t h e i n t e n s i t y of Hoc
l i n e , width of H l i n e and t h e • importance* e t c .
f h e r ^ a t i n g of the ' i a ipor tance* of the f l a r e s
i s done on t h e s c a l e 1 , 2, 3 and i s a somewhat s a b -
j e e t i v e measure , f h e imj>ortance g i v e n t o t h e f l a r e s
i s merely based on t h e a r e a and t h e i n t e n s i t y of the
f l a r e . H a r e s oove r i ag m a r e a up to 250 m i l l i o n t h s
of t h e s o l s r d i s k a re r a t e d of impor tance I j t hose
hav ing s r e a 250 t o 600 m i l l i o n t h s a r e c l a s s e d i n 2}
whi le t h o s e wi th a r e a above 600 m i l l i o n t h s a r e c l a s s e d
a s 3 . However, t h e s e l i i a i t s a r e not r i g i d ; they can. be
a d j u s t e d i f t h e f l a r e i s e x c e p t i o n a l l y b r i ^ t o r weak
f o r i t s a r e a , and some t imes -tt or - s i g n s a r e addid t o t h e impor tance r a t i n g ( s e e Table 4 . 1 ) . f h u s t h e impor tance o f t h e J t lare I n d i c a t e s i t s s i z e and t h e i n t e n s i t y .
» a}
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152
Llat of a a s l l s o l a r f l a r e s f o r t h e perloQ Jajiiasi^ t o August, 1058,
froffi
Month Bate t Beginning ' h r e . ( U . f . )
I n p o r t a n c e . 1
tianuary 1 9 6 8 , , , « 2 0557
15 0009 16 09g? 1 2S 0520 1 84 0334 1 g6 2
Febrimfy 1 9 5 8 . , . . 4 0539 1
4 0901 1 11 0252 1 11 0532 1 12 0937 1 13 0144 1 E5 0i5S 86 0449 1 28 0438 1
Harch 1 9 5 8 . , , 8 1060 - —
10 0210 IS 0344 14 0442 17 0438 17 10^ 1 2 1 1040 22 0S41 23 1016 a 2S 0257 1 25 0529 2 2§ 0557 2
Cont d . • .
153
- (11) -
Month 1 Date Beginning ^ ' h re* {U.T.)
Ifflportanoe.
March 1958 27 1 31 0856 1 3 i 1025^ 1"
A p r i l 1 9 6 8 . . 1 Olii5 1 2 1 2 0502 2 3 I 7 l o g a 8 8 Q^Oh. 1
16 0535 1" 28 105S r
May 1 9 5 8 , . . « 1 xom r 2 0646 1 5 G407 1+ 8 054'9 1
30 0326
^ime 1958,.,. 6 0520 5 0800 6 0438 6 0458 2
10 0307 1 10 0602 1 11 0552 1 11 6231 14 0630 1 18 0319 1 18 0538 1 19 0456 i l 19 10C3B 19 0212 2 S6 0300
Ju ly 1 9 5 S . . . ^ O3O? 26 0205 1
Ll^gr OF PUBLIGATIOHS
1, '"CGSiuic-Ray I n c r e a s e Associa ted W|fch A isiaall i^olar F la re" I n d . J , Meteorology and Geophysics, Vo l . I I , Ko,2, 169Xia5®)
'•LATITTOS DEPSNDENGE OF AMPLITUDE AND PHASE OF THE ®UR»Afl VARIATIOH" Nat,Acad.i3c(.,In<^a, V o l . 3 3 , Sec.A, psiM 2 , ' 213 (1963)
3 . "DITJRML VARIATION OF CObMIC RAY INTSNblTY AT GULMARG ( X=24.7 I?)" Nat . Acad. Set I n d i a , V o l . 3 4 , bec.A, p a r t I 53 (1964)
4. " R E U T I f H ^ P BJITWEEN THE SOLAR kW MAGNETIC PHEMOMEHA WITS COa!IC BAY INTENSITY" Ha t . Acad. ScC I n d i a , Vol34f, Sec .A p a r t 4 , 561 (13S4) .
5 . "EXPSMMSITAL ARRAMGEMSHT OF M2S0N CUBICAL TELESCOPE AS WELL AS NARROW ASGLB TELESCOPES" i s p re sen ted i n the cosmic-r ay syraposiua h e l d a t Bcsnbay i n 1959.