CRITERIA OF INTERPLANETARY PARAMFTERS CAUSING INTENSE MAGNETIC STORMS ( D s t < -100 nT)

Walter D. Gonzalez*

and

Bruce T. Tsurutani

Jet Propuls ion Iabora tory C a l i f o r n i a I n s t i t u t e of Technology

4800 Oak Grove Drive Pasadena, Ca l i fo rn ia 91 10 9.

January 1987 -

Submitted to P lane ta ry and Space Sciences

* *also a t t h e I n s t i t u t o de ksquisas Espaciais, Sa0 Jose dos Campos, Braz i l

https://ntrs.nasa.gov/search.jsp?R=19880006818 2020-01-26T08:27:57+00:00Z

. . . _. .I. ~ ._

CRITERIA OF INTERPLANFTARY PARAMETERS CAUSING INTENSE MAGNETIC STORMS (Dst < -100 nT)

Ten intense maqnetic stonns (D,t < -100 nT) occurred during the 500 days of I Auqust 16, 1978 to December 28, 1979. Frun. our analysis of ISEE-3 field and

plasma data, it is found that the interplanetary cause of these storms are long-

duration (> 3 hours), larqe and neqative (< -10 nT) IElF BZ events, associated

with interplanetary duskward-electric fields > 5 mV/m. Because we find a one-tc-

one relationship between these interplanetary events .and intense stom, we

sugqest that these criteria can, in the future, be used as predictors of intense

storms by an interplanetary monitor such as ISEE-3. These BZ events are found to

occur in association with larqe amplitudes of the ItlF,magnitude (13-30 nT) within

- two days after the onset of either high-speed.solar wind streams or of solar wind

density enhancement events, qivinq important clues to their interplanetary origin.

Some obvious possibilities will be discussed. The close proximity of the R, events

and magnetic storms to the onset of hiqh speed streams or density enhancement

events is in sharp contrast to interplanetary Alfven waves and HILDCAA events

previously reported by the authors (Tsurutani and Cbnzalcz, 1986) and thus the

two interplanetary features and correspmding qeomaqnetic responses can be thought

of as being complementary in nature.

An examination of opposite polarity (northward) RZ events with the same cri- - teria ( , > 3 hrs, Bz > 10 nT) s h o w that their occurrence is similar both in

number as well as in their relationship to interplanetary disturbances, and that

they lead to low levels of gemgnetic activity.

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_I-____

Althouqh 90% of the events were associated with high-speed streams and

interplanetary shocks, the amplitude of the storms had little dependence on the

. strenqth of the shocks.

1. 1 N T m m 1 o N

The origin of gecmaqnetic storms in the interplanetary medium has been .

investigated for over two decades ( e .q . , Akasofu and Chapman, 1963; review by

Akasofu, 1981). The suggestion that the southward canponent of the IMF (-BZ in

solar maqnetospheric coordinates) as the dominant parameter responsible for the

development of the storm's main phase has proven to be successful toward a

mantitative understanding of the origin of such developnent (e.g., Rostoker and

Falthmr, 1967; Russell et al., 1974; Burton et al., 1975; Perrault and

Akasofu, 1978; Feldstein et al., 1984). However, we are still far fran the final

stages of this quantitative understandinq toward the goal of predicting the

occurrence of a geomagnetic storm frm the knowledqe of interplanetary parameters.

Furthermore, the solar apd interplanetary origins of southward IMFs are presently . .

almst totally unknown.

The purpose of this paper is to study the solar wind origins of geamagnetic

stonns by using the unique (practically continuous) observations provided by the

ISEE-3 satellite while it was at i t s halo orbit around the sunward libration '

pint (abut 240 earth radii in front of the earth). During the selected time

interval for our study (August 16, 1978 to December 28, 1979) the satellite - provided a full set of maqnetic field (Frandsen et al., 1978) 2nd plasma (Bame et

al., 1978) data. The Dst plots used for the identification of maqnetic storms

were kindly prepared by the @ophysical Institute of the University of Alaska.

I n this report we present the results obtained for a class of intense magnetic

storms, defined by the storm-index Dst being less than -100 nT. The restriction

- . '-

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to t h i s class of stoms provided u s a l imited set of e v e n t s s u i t a b l e f o r a d e t a i l e d

study. With the criteria used to select i n t e n s e storms, only t e n even t s were

found dur inq t h e SO0 days of our d a t a set, wi th peak Dst va lues ranqinq between

-110 nT and -220 nT.

To complete o u r s tudy, we have also incJuded a complementary a n a l y s i s of

northward IMF €32 events. Jbk -use the same i n t e r p l a n e t a r y criteria t h a t was dis-

covered for t h e causes of magnetic storms (except northward rather than southward

f i e l d s ) , and determine t h e northward IMF even t s ' rate of Occurrence, solar wind

stream dependence and geomagnetic effects.

I n add i t ion , a s tudy of t h e role of i n t e r p l a n e t a r y shocks on t h e developnent

of t h e main phase of q e m g n e t i c s torms is b r i e f l y discussed.

2. INTENSE STORM EVENTS AND INTERPLANFTARY CONDITIONS.

Recause the sea rch for r e l a t i o n s h i p s between qeomagnetic storms and inter-

p l ane ta ry shocks has been a matter of primary i n t e r e s t for many y e a r s (e.q.,

Akasofu and Chapman., 1963; Akasofu, 1981; Srnith e t a l ; 1986), w e s ta r t t h i s

s e c t i o n w i t h a s tudy of t h e r e l a t i o s h i p between t h e amplitude of a g e m q n e t i c

storm (peak Ds t va lue ) and t h e s t r e n g t h of the i n t e r p l a n e t a r y shock preceedinu it.

Information on t h e i n t e r p l a n e t a r y shocks t h a t occurred during t h e time i n t e r v a l

of our study, as ident i f ied and d iscussed by Tsurutan i and Lin (19851, Smith et

al. (1986) and Ravassanc-Cattaneo et a l . (1986), have been used i n order to

compare the i r s t r enq ths wi th t h e i n t e n s i t i e s of magnetic storms. Smith et al . - (1986) have presented a detailed s tudy about a d e f i n i t e r e l a t i o n s h i p between t h e

Occurrence of storm sudden c m n c e m e n t s and t h e presence of i n t e r p l a n e t a r y

shocks.

F igure 1 shows t h e normalized occurrence of shocks, €or selected i n t e r v a l s

of t h e i r s t r e n q t h s , as a func t ion of peak Dst va lues of t h e magnetic storms t h a t

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occurred within an expected time laq (0-3 days) after their arrival to the Earth’s I magnetopause. The shockswere grouped in three classes: weak, medium and strong?

’ . accordinq to their correspondinq high speed stream’s velocity increase: V < It is noted in 100 km s-l? V = 100-250 km s-1 and V > 250 km s-1, respectively.

this figure that there is no indication for any clear relationship between shock-

strength and amplitude of the magnetic storms. Bdth weak and stronq shocks seem

to have similar possibilities of being related to maqnetic storms of a given

. .

amplitude. There is sane indication. frm this limited data set that the most

intense maqnetic stom (with peak Dst values > 150 nT) are related to medium-

strenqth shocks.

’-

Figure 2 schematically shows features related to the ten intense storms that

occurred during the time interval of our study. For each of them, the peak value,

the date and the approximate UT (n&r between parentheses) of the Dst events are

indicated at the end of each case. All these event‘s involved the presence of

long duration, large and neqative values of the IPIF BZ component (see discussion

below) within one to three hours prior to the Dst event (after the solar wind

transit time of about one hour between the satellite position and the maqnetopause

has been subtracted). The corresponding peak B, values are indicated in this

figure. All these BZ events occurred during t h e intervals with large IIE’ If31

values. The corresponding peak IBI values are also given in this figure.

The presence of interplanetary shocks were identified for nine of the events,

Figure 2 also shows the within a time interval of 0-2 days prior to the events.

approximate times of their observations at ISEE-3 together with their correspond-

inq magnetosonic Mach numbers. Finally, for the one event where a shock was not .

present, a tyw of a non-compressive density enhancement (NCDE) event (Gosling et

al., 1977) was identified, and is indicated in this figure.

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Figure 3 illustrates one of the nine Dst events that occurred in association

with an interplanetary shock (April 4, 1979). The magnetic storm had a particu-

larly high intensity (peak Dst 200 nT). However, the associated interplanetary

shock was weak (Mach number The amplitude of the Dst

event is argued to he related to the larqe amplitude, long duration, negative BZ

event followinq the shock. The stronqer shock at the heqinninb at April 5, 1979

1.0, - V < 100 km s” ) .

. . . .

(Wach number 3.0, V 250 km s”) did not cause a major storm (Dst -50 nT)

because BZ was larqely northward durinq that event. The two interplanetary shocks

can be easily identified by the abrupt magnetic field and velocity increases

(plus density and temperature increases) indicatinq the occurrence of fast fomard

shocks (Tsurutani and Lin, 1985; Smith et al., 1986).

Figure 4 shows the Dst event of September 18, 1979 that did not involve the

The intense storm followed a large amplitude, long duration, presence of a shock.

negative BZ event, as in the prior case. However the event is preceded only by a

larqe density enhancement event. This is similar to non-compressive density

enhancements, as described by &slincr et al. (1977).

3. r o m m IMF B~ EVENTS.

Because the intense maqnetic storms discussed above were associated to long-

duration (> 3 hours), larqe-amplitude IVF RZ ( < -10 nT) events with related

electric field amplitudes > 5 mV/m, a natural question arises with respect to the

occurrence frequency, association to interplanetary features and related qemaq-

netic activity levels of similar IMF BZ events with the opposite (northward)

polarity. We have made such a study and present the results below.

Fran a statistical study of the s~ IMF and plasma data set used in the

previous section, it is found that eleven opposite IMF BZ polarity events occurred

during the same time interval. These events are listed and described in Table 1.

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Column one qives t h e dates and the approximate Universal Times f o r t h e o n s e t of

the IMF BZ events . Amonq these eleven northward E2 events , t h r e e followed or

preceded neqat ive '32 even t s (discussed i n t h e previous s e c t i o n ) and are thus

ind ica ted by an a s t e r i s k . The second and t h i r d columns of t h i s table q i v e the

peak RZ va lues ( i n nT) and t h e du ra t ion ( i n hours) of t h e events , respec t ive ly .

The f o u r t h column g i v e s t h e peak IBI values dur ing these events. The f i f t h

column q i v e s information on the r e l a t i o n s h i p of the even t s to i n t e r p l a n e t a r y

. shocks (n ine cases) or to NCDE even t s ( t w o cases). The approximate lag times ( i n

hours) of t h e even t s wi th reswct to t h e shocks and also the shock s t r e n g t h s

( ind ica t ed by t h e i r maqnetosonic Mach numbers) a r e ' g i v e n i n this column. For t h e

cases with ze ro lag-time ( i n d i c a t e d ) , t h e Bz event followed the i n t e r p l a n e t a r y

shock wi th in t h e same hour. The NCDE events a s soc ia t ed w i t h two of the cases

preceded t h e p o s i t i v e RZ even t s by a f e w hours to less than one day. The last

t w o columns of Table 1 g i v e information on t h e qeanagnet ic a c t i v i t y durincr t h e

even t s , as measured by t h e AE and Dst indices . A t r a n s i t time of a b u t one hour

hetween sa te l l i t e and magnetopause was assumed i n t h e t ab le . The AE a c t i v i t y was

considered to be "zero" when AE < 100 nT. I n the Dst column, t h e letter "R"

s t a n d s f o r a recovery phase of a magnetic storm, t h e letter "Q" for a def ined

quiet-world day and the "plus" symbol for t h e e x i s t e n c e of p o s i t i v e va lues of D,t

associated w i t h solar wind r a m p res su re increases .

Figure 5 is one example (November 11, 1979) among t h e n ine p o s i t i v e Bz events

t h a t occurred i n a s s o c i a t i o n with an i n t e r p l a n e t a r y shock. As s h w n i n Table 1,

t h i s even t l a s t e d approximately s i x hours wi th peak Bz values around +20 nT. The

even t followed an i n t e r p l a n e t a r y shock by about 12.5 hours. The shock 's onse t

was about 0130 UT of t h e same day and had a Mach number of 2.5. During t h i s

'event , t h e AI? and Ds t va lues were very low (around ze ro ) , apart from a p o s i t i v e

D,t increment due to solar wind ram pressu re increases .

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This event also has one of the lonqest (about two days) and continuous

northward BZ duration. Notice that when BZ is still positive, but < 10 nT (0600-

3400 UT November 12), the AE activity is non-negliqible (up to a 300-nT level).

However, there are very larqe By values (up to 18 nT) after 0300 UT which may be

related to reconnection via a maqnetic confiquration described by Cawley (1979).

The AE increase occurs approximately one hour'after the arrival of the strona By

fields to the maanetosphere. -m .

Figure 4 is an example (Sentehr 18-19, 1979) of a positive BZ event that

occurred in association with an NCDE event. This case is an example of a d i n e d

negative/positive €37, event, from which the negative part was associated with an

intense magnetic storm. The relationship of this event to that of the NCDE event

is not obvious and is presently under study. The positive F32 event lasted for

about three hours. During this time, the AE values were close to zero and the

Dst values showed a recovery from the magnetic storm associated with the precedinq

negative B, event.

by the letter "0" in Table 1.

This period corresponded to a World Ouiet Day, as indicated .

4. DISCUSSION

Althouqh Figure 2 shows only the peak values of the BZ events that arrived

to the maqnetopause approximately one to three hours prior to the occurrence of

the peak values of the ten intense s t o m , a c m n feature found for all those

storms was the presence of lonq duration ( > 3 hours), larqe and negative values

(<-lo nT) of the IMF BZ component, with the associated interplanetary duskward

electric field havinq values > 5 mV/m. Additionally, it was found that there

were no other interplanetary events metinq these criteriadurinq the interval of

study, qivinq a one-to-one correspondence between intense magnetic storms and

.

interplanetary RZ events of this type. Furthermore, the Bz events which had

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c h a r a c t e r i s t i c s nea r t h e threshold val.ues s e e m to correspond to rnaqnetic storms

wi th peak D s t va lues close to -100 nT, t h u s suqges t ing t h a t t h i s r e l a t i o n s h i p may

’ . also extend to moderate storms.

A detailed s tudy of this i n t e r e s t i n q correspondence, as well as of its

r e l a t i o n s h i p to in t e rp l ane ta ry m a n t i t i e s t h a t involve BZ (e.q. , P e r r a u l t and

Akasofu, 1978; Masofu , 1981; Murayama, 1982: Baker e t a1.8 1983; Tsurutan i e t

alar 1985: Qnzalez, 19861, fa l ls o u t s i d e t h e scope of the presen t work. Never-

theless, we can advance t h a t the RZ’ f lux (duskward electric f ie ld) va lues when

in t eg ra t ed across t h e i r corresponding d u r a t i o n s ( > 3 hours) , show a fa i r ly clear

p o s i t i v e l i n e a r r e l a t i o n s h i p with t h e peak Dst va lues ( c o r r e l a t i o n c o e f f i c i e n t of

about 0.75). When the d u r a t i o n factor is suppressed, t h e c o r r e l a t i o n decreases

quite s u b s t a n t i a l l y . Notice t h a t such a r e l a t i v e l y high c o r r e l a t i o n c o e f f i c i e n t

of 0.75 was found even without takinq i n t o account loss processes durinq t h e

d e v e l o p n t of these i n t e n s e storms. Therefore, a t Ieast f o r i n t ense storms, it

is argued t h a t n o t on ly t h e amplitude but also the dura t ion of t h e nega t ive BZ

even t s have d e f i n i t e con t r ihu t ions for t h e development of the storms. Previous

s t u d i e s on t h e B, r e l a t i o n s h i p to storms gave much a t t e n t i o n mostly to t h e ampli-

tude of Bz (Burton e t al., 1975; Murayama, 1982), a l though suqges t ions about the

importance of t h e RZ event-durat ion were advanced by Russell. e t al. (1974) w i t h

respect to moderate s t o m , and by o t h e r au tho r s w i t h respect to substorms and

geomaqnetic a c t i v i t y p r e d i c t i o n s (e.g., Arnoldy, 1971; Jose lyn et a l . , 1981).

As shown i n Fiqure 2 and Table 1, t h e occurrence frequency and a s s o c i a t i o n - to i n t e r p l a n e t a r y f e a t u r e s of both southward and northward BZ even t s are very

s imi l a r . Thus, dur inq the 500 days of ou r s tudy , t e n (e leven) southward (north-

ward) BZ even t s occurred wi th in t w o days after t h e o n s e t of e i t h e r a high-speed

stream (n ine cases for both types of BZ even t s ) or of a d e n s i t y enhancement (one

case for a southward Bz even t and t w o cases for northward RZ events ) . Both types

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of Bz events also occurred during time intervals with large values of the total

interplanetary magnetic field intenisty (13-30 nT for southward BZ events and 14-

40 nT for northward F3z events).

The similarities between both types of BZ events represent important clues

for studies of their interplanetary origins. Interplanetary processes closely

responsible for both types of BZ events are under present investigation. Sane

interplanetary structures that seem to be related are the following: 1) B, struc-

tures existing upstream of high-speed streams which get amplified by shock can-

pression, 2) turbulent fields that are produced in stream-stream "interaction re-

. - .

gions" between hiqh-velocity streams overtaking a'lower velocity streams (Dessler

and Fejer, 1963; Smith and Wolfe, 19781, 3 ) Kinky heliospheric current sheets

(Tsurutani et al., 1984) that occur in hiqhly compressed regions between solar

flare-associated shocks and the cold driver gases,. 4 ) magnetic clouds (Klein and

Burlaga, 1982), that are either magnetic tonwes associated with solar dis-

turbances or are detached "bubbles".

The level of qecmagnetic activity during the positive BZ events was generally

quiet (Table 11, even though such events followed large-scale "active" solar wind

features such as hiqh-speed streams and NCDE events. It should be noted, however,

that a non-negligible. level of AE activity ( 100-200 nT) and a r e q k of

recovery phase frun a magnetic storm were present in sane cases. The storm

activity was related to the large amplitude-southward BZ fields that scmetimes

follow the onset of hiqh-speed streams or of NCDE events, as in the negative BZ

events of Section 2. On the other hand, the low-level At3 activity could be

associated with convection enhancement caused by the solar wind velocity increases

via a viscous-type of interaction, and/or to the large-amplitude values of the

IMF By c-nent, via a By dominant reconnection event. In either possibility,

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the enhanced convection is expected to be on ly of minor amplitude (e.g., e n z a l e z

and Mozer, 1974, Mozer, 1984) when compared to t h e much l a r g e r ones produced by

. southward BZ events .

The i n t e n s i t y of t h e smal l AE a c t i v i t y related to t h e p o s i t i v e RZ even t s

correlated very poorly wi th the shock s t r e n g t h ( c o r r e l a t i o n c o e f f i c i e n t only

around 0.15). Th i s ccmplements the r e s u l t s &eviously mentioned reqarding t h e

l ack of any c o r r e l a t i o n between t h e i n t e n s i t y of maqnetic storms and t h e s t r e n g t h

of t h e shocks t h a t preceded them.

Recently, Akasofu and Tsuru tan i (1984) reported unusual a u r o r a l f e a t u r e s

r e l a t e d to a n event. that looks very similar to a. p o s i t i v e Bz event . Thus, t h e

even t s repor ted i n t h i s s e c t i o n can be s tud ied i n t he contex t of mqne tosphe r i c

f e a t u r e s that are mostly no t y e t understood.

5. CoNcLuSIms.

I t was shown t h a t t h e in t e rp l ane ta ry ' cause f o r t h e two ' i n t e n s e magentic

s torms (Dst < -100 nT) that occurred from August 16, 1978 t o December 28, 1979,

were lonq d u r a t i o n (> 3 hours ) , large and negat ive ( < -100 nT) IFF RZ even t s ,

associated with. i n t e r p l a n e t a r y duskward - electric f i e l d s > 5 mV/m. Because w e

f i n d a one-to-one r e l a t i o n s h i p between these i n t e r p l a n e t a r y events and in t ense +

s t o m , w e sugqes t t h a t t hese criteria can, i n t h e f u t u r e , be used as a predictor

of in t ense storms by an i n t e r p l a n e t a r y monitor such as ISEE-3. However, a study

on t h e r e l a t i o n s h i p of these criteria t o o t h e r q u a n t i t i e s argued to be associated

to magnetospheric a c t i v i t y , such as i n Akasofu ( 1 9 8 l ) , remains to be 'done.

These RZ e v e n t s are found to occur i n association wi th large ampli tudes of

-

the IMF maqnitude wi th in t w o days a f t e r t h e onset of e i t h e r a high-speed stream

or of a d e n s i t y enhancement event . An examination of s i m i l a r opposite p l a r i t y

(northward) RZ even t s showed t h a t t h e i r occurrence is similar both i n number as

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I w e l l as i n t h e i r r e l a t i o n s h i p to i n t e r p l a n e t a r y d is turbances . This may suggFlctst

to u s t h a t both types of BZ even t s may be due to random f l u c t u a t i o n s of the

' i n t e rp l ane ta ry magnetic f ie ld i n and o u t of t h e ecliptic plane. Th i s could p u t '

seve re l i m i t a t i o n s on t h e p o s s i b i l i t y of p r e d i c t i n g such even t s by solar observa-

t i ons . On t h e o t h e r hand, t h e f a c t t h a t t hese Bz even t s o c c u r - w i t h i n 0-2 days

after t h e o n s e t of a high-speed stream or of a d e n s i t y enhancement event , and

t h a t they a l so-occurred dur ing t h i n t e r v a l s w i th large va lues of t h e total IMF

i n t e n s i t y , g i v e important c l u e s to their i n t e r p l a n e t a r y o r i g i n . C e r t a i n l y t h e

p r e d i c t a b i l i t y of t h e occurrence of such features are i n o u r reach wi th in the

near-future.

F ina l ly , a l though n ine of t h e t e n storms involved the presence of high-speed

streams, it was shpwn t h a t t h e shock s t r e n g t h and t h e i n t e n s i t y of t h e storm are

no t c o r r e l a t e d a t a l l , leav ing t h e importance . . of i n t e r p l a n e t a r y s h o c k s - r e s t r i c t e d

mainly to the s tudy of sudden storm camencements ( S m i t h et al., 1986). I n

a d d i t i o n , it w a s also found t h a t t he i n t e n s i t y of t h e small AE a c t i v i t y related to

t h e p o s i t i v e Bz even t s correlated very poorly wi th t h e shock s t r e n g t h ( c o r r e l a t i o n

c o e f f i c i e n t of on ly 0.15).

T h i s work was performed a t t h e Jet Propuls ion Laboratory, C a l i f o r n i a I n s t i -

One of t h e au tho r s (W.D.G.) would tute o f Technolcqy under c o n t r a c t wi th NASA.

l i k e to acknowledge t h e National Research Council - NASA Resident F.esearch Asso- -

c i a t e s h i p Proqram for support while i n tenure. a t JPL. The au tho r s would also

l i k e to s i n c e r e l y thank Dr. E. J. Smith and Dr . S.J. Rame f o r t h e ISEE-3 data as

w e l l as Prof. S. I . Akasofu f o r t h e Dst and AE plots.

-1 1-

E'ICxlRE CAPTIONS

Figure I: Normalized Occurrence of i n t e r p l a n e t a r y shocks, dur ing August 16, 1978

- December 28, 1979, wi th selected s t r e n g t h i n t e r v a l s ( s t ronq , medium, and weak)

as func t ions of t h e i n t e n s i t y of t h e r e l a t e d magnetic storms (given by peak D,t). b

Fiqure 2: Schematic r ep resen ta t ion of t h e ten' events . For each of them, t h e

approximate times (Universal Time) and magnitudes r e l a t e d to peak Dst , peak R,,

peak (Bf and to t h e i n t e r p l a n e t a r y . shocks are shown. The shock magnitude

( s t r e n g t h ) is given by t h e Mach number. The even t wi th an a s t e r i s k had discon-

t inuous da ta .

Fiqure 3: Example of the i n t e r p l a n e t a r y magnetic f i e l d and sane of the plasma

d a t a measured by ISEE-3. Corresponding va lues of AE and Dst are also p l o t t e d .

I n t e r p l a n e t a r y shocks of smal l and large maqnitudes are indica ted wi th s and S ,

r e spec t ive ly . (The Cfach numbers for s and S are about 1 and 3, r e s p e c t i v e l y ) .

Figure 4: Event wi th no i n t e r p l a n e t a r y shock present . The d e n s i t y pane l shows

an enhancement of a NCDE type, poss ib ly r e l a t e d to t h e BZ and &t events .

Figure 5 : I n t e r p l a n e t a r y magnetic f i e l d and plasma d a t a measured by ISEE-3 for

t h e event of November 11, 1979. Corresponding va lues of AE and Dst are also

plotted.

PSFERENCES - Akasofu, S.-I., and S. Chapan , The deve lopwnt of t h e main phase of magnetic

s t o m , J. Ceophys. R e s . , 68, 125, 1963. - - - Akasofu, S.-I., Energy couplinq between t h e solar wind and t h e magnetosphere,

Space Sc i . Rev., - 28, 111, 1981.

Akasofu, S.-I., and B.T. Tsuru tan i , Unusual a u r o r a l f e a t u r e s observed on January 10-11, 1983, and t h e i r p o s s i b l e r e l a t i o n s h i p s to t h e i n t e r p l a n e t a r y magnetic f i e l d , M p h y s . Res. Lett., c, 1086, 1984.

-12-

Arnoldy, R. L., Siqnature in the interplanetary medium for suhstorms, - J. Gmphys. Res., 76, 5189, 1971 - -

Baker, D.N., R.D. Zwickl, S.J; R a m , 'E.W. Hones, Jr., B.T. Tsurutani, E.J. Smith, and So-I. Akasofu, An ISEE-3 high time resolution study of interplanetary parameter correlations with maqnetospheric activity, - J. Gophys. - - Res., 8 8 , 6230, 1983.

Bame, S.J. , J . R . Asbridge, H.E.Felthauser, J.P. CDre, H.L. Hawk and J. Chaves, ISEE-c Solar wind plasma experiment, IEEE. 'Trans. msci. Electron. 8 (32-16, 160, 1978.

Bavassano - Cattaneo, M.B., R.T. Tsurutani, E.J. Smith, and R.P. tin, Subcritical Magnetic field and energetic par- and supercritical interplanetary.shocks:

ticle observations, to appear in 2. Gmphys. Res., 1986.

interplanetary conditions and Dst, - J. Geophys. I_ Res., - 80, 4204, 1975. . Burton, R.K. , R.L. McPherron, and C.T. Russell, An empirical relationship between

Cowley, S.W.H., "On the distribution of % in the Geanagnetic' Tail", Planet. Spa. Sci., - 27, 769, 1979.

Nssler, A. J., and J. A. Fejer, Interpretation of Kp index and M-reqion aeanag- netic storms, Planet. Space - Sci;, 11, 505, 1963.

Feldstein, Y . J . , V. Yu. Pisarsky, N.H. Ruclneva, and A. Grafe, Ring current simulation in connection with interplanetary space conditions, Planet. Space Sci., 32, 975, 1984.

Frandsen, A.M.A., R.V. Connor, J. Van Amersfoort, and E . J . Smith, the ISEE-C . Vector Helium !laqnetmter, IEEE Trans. Ckosci. Electron., (22-16, 195, 1978.

Cbnzalez, W.D., and F.S. Mozer, A Ouantitative model for the potential resulting €ran recorinection w i t h an arbitrary interplanetary magnetic field, - J. Wphys. - Res., 2, 4186, 1974.

anzalez, W.D. , Electric field and enerqy transfer from the solar wind to the Earth's magnetosphere, to appear in -- Solar Wind - Maqnetosphere Coupling, eds. Y. Kamide and 3.A. Slavin, D. Reidel, Holland, 1986.

Goslina, J.T. , E. Hildner, 3 . R . Asbridge, S.J. Rame and W.C. Feldman, Non- mpressive density enhancements in the solar wind, - J. mphys. - 7 Res., 82, 5005, 1977.

Joselyn, J . A . , J. Hirman, and G.R. Heckman, ISEE-3 in real time: an update, _c Eos, Trans. Am. eophys. 7 - Un., 62, 617, 1981. - 7

Klein, L.W., and L. F. Rurlaqa, Interplanetary Magnetic Clouds at 1 AU, - J. Cbophys.

Mazer, F.S., Electric field evidence €or viscous interaction at the magnetopause,

- Res., 87, 613, 1982.

Cbophys. Res. Lett., 11, 135, 1984. -- -

-13-

Murayama, T., Couplinq func t ion between solar wind parameters and qeanagnetic ind ices , Rev. &ophys. Space Phys., - 20, 623, 1982.

1 . Perrault, P.D. , and So-I. Akasofu, A s tudy of qecmagnetic s u b s t o m , Ceophys.

-

J. R. Astron. Soc., 54, 547, 1975. - - - - Rostoker, G o t and C.-G., F a l t h m r , Re la t ionsh ip between chanqes i n t h e i n t e r -

Dlanetary m q n e t i c f i e l d v a r i a t i o n s i n the maqnetic f i e l d . a t the earth's su r face , - J. pmphys. - - Res., 72, 1967.

Russe11, C.T., R.L. McPherron, and R.K. Burton, On the cause of q m q n e t i c s t o m , J. Ckophys. - Res . , 2, 1105, 1974.

L

Smith, E..J., J.A. Slav in , R.D. Zwick l , and S.J. Bame, Shocks and storms sudden cmmencements, -- S o l a r Wind-Maqnetosphere Coupling, eds., Y. Kamide and J.A. S l a v i n , D. Reidel , Holland, 1986.

Smith, E.J., and J . H . Wolfe, Pioneer 10 and 11 obse rva t ions o f evolving solar wind s t reams and shocks beyond 1 All, i n -- Study of Trave l l i ng I n t e r p l a n e t a r y Phenanena, ed. N.A. Shea et al., D. Reidel, Hinqham, MA, 227, 1977.

Tsu ru tan i , R.T., C.T. Russe l l , J.H. Kina, R.D. Zwick l , and R.P. Lin, A kinky h e l i o s p h e r i c c u r r e n t sheet.: cause of CWW-6 suhstonns, Ckophys. - Res. - - Lett., 11, 339,*1984.

Tsuru tan i , R.T., and R.P. Lin, "Accelerat ion of > '47 KeV Ions and > 2 KeV e l e c t r o n s by i n t e r p l a n e t a r y shocks a t 1 AU," - J. Oeophys. - - Pes. 90, I, 1985.

Tsu ru tan i , R.T., J.A. Slav in , Y. Kamide, R.D. Z w i c k l , J .H . Kinq, and C.T. R u s s e l l , Coupling between the solar wind and t h e magnetosphere: CMW 6, J. Ckophys. Pes. , 90, 1191, 1985. - - -

Tsun i t an i , R.T., and W.D. Cbnzalez, The cause of h igh- in tens i ty long-dura t ion cont inuous AE a c t i v i t y (HILDCAFs): i n t e r p l a n e t a r y Alfven wave t r a i n s , to appear i n P lane t . Spac. Sci., 1986. -

0

-14-

n

U ca

n

4

m 0 .3 0 3 ?> 9 0 3 0 3 O D VI 0 VI VI U

C ’ aJ > 01

W

N m aJ > +( U ri m 0 a

a 4 2 v) C 0 ri U a d Q) c4 I 2d V 0 I: cn

Ll CaJ v n a e = 2

4 d m N N N

. e e 4 rn . . 4 I 0% 0% N h

I N 1 lw h) h( 4 9 N

n C 01 > 01 d 01

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e

01

5 0 U

0 m S N el 9 N U m 0 m 0 VI N N 1 m U N m 4 U

01 U a

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hl VI

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9 h

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u 9 urn v 4 v 3 3- 3-

nom 3.. .Po?

STRONG SHOCKS AV > 250 kmls

0

100

0

100

MEDIUM SHOCKS AV = 100-250 kmls

I . . 1 I

WEAK SHOCKS AV < 100 ltmls

Figure 1

.. . . , . ..._., , .~ .- . -.. ,.-.--* .... - . , Y".

, - . .

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n I- C

t w g n .

a I

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t :E

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P

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0

I b,E

1%

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1 - L Y Q o - 0 n x 3 W,

v) cv x 00

F I

Vs,, km s-l

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-

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-100 -200

nT

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IBl, nT

AE, nT

40

’ 20

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I I I I

Figure ‘3

T , Ktxld) P

km 5-l sw' V

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800 C I I 1

400 0

1100

650

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I

0

I I -- I I I

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. u -100 -200 l- I I I

16 17 18 19 SEPTEMBER 1979

Figure 4

’ 1100 I , I I - -

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0 - DsY nT -100

-200

20 I

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BZ, nT 0 - I I

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1 1 I -

1500 1 I 1 I -

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-

Figure 5

AUTORIZAC~O PARA PUBLICAC~O AUTHORIZATION FOR PUBLICATION

r PALAVRAS CHAVES/KEY WORDS

gg INTERPLANETARY-MAGi’VETOSPHERE COUPLING 2; INTERPLANETARY MAGNETIC FIELD 33 a GEOM4 GNETiC STORMS

DISTRIBUICAO/DISTRIBUTION AUTOR RESPONSAVEL RESPONSIBLE AUTHOR

0 INTERNA / INTERNAL

EXTERNA / EXTERNAL

0 RESTRITA / RESTRICTED

CDU/UOC DATA / DATE

550.385.4 August, 1987

PbBLICAFaO N 9

I I PUBLICATION NO

I I INPE-4 306-PRE/1172 I W \

2 INTENSE K4GA’ETIC STORMS (Dst -100nT)

-I

CRITERIA OF INTERPLANETARY PARAMETERS CAUSING I-

C /

O R I G E M ORIGIN (-’ DGA PROJETO PROJECT

PA GATT ULTIMA WG.-

r N 0 N O ; P A G E S T DE PAG. LA;; PAGE

\ A r

y ~ ~ ~ l s l f t o ~ N O DE MAPAS -. NO OF MAPS

.ONGINAE PAGE IS ol3 I ‘ W R QUALITY

RESUMO-NOTAS/ABSTRACT- NOTES

Ten in tense storms (Dst < -100nT) occurred during the 500 dzys of August 16 , 1978 t o December 18, 1979. From our analysis of ISZE-3 fZeZE and p l a s m data, it i s found t h a t the interpZanetary cause of these storms are long-duration ( > 3 hours) , large and negative ( < -lOnT! IMF B , events , associated with interplanetary duskward-electric f i e l d s 5mV/m. Because ue f i n d a one-to-one reZationship between these interpzanetary events and in tensc storms, we suggest thct these c r i t e r i a can, i n the f u t u r e , be used as predictors of intense storms by an i n t e q l a n e t a r y monitor such as ISEE-3. These B , events are found t o occur i n associat ion with large anpl i tudes of t h e I M F magnitude (23-30nTl wi thin two days a f t e r the onset of e i t h e r high- speed solar wind streams or of solar wind densi ty enhancement events , giving important c lues t o t h e i r interplanetary or ig in . Some obvious p o s s i b i z i t i e s w i l l be discussed. The c lose proximity of the B, events and ,mgnet ic s t c r r s t o t h e onset of high speed streams or dens i ty enhancement events i s i n sharp contrast t o interplanetary Alfven waves and HILDCAA events previously reported by the authors (Tsurutdni ahd Gonzalez, 1986) and thus t h e two interplanetary f e a t u r e s and corresponding geomagnetic responses can be thought of as being complementary i n nature. An examination of opposite p o l a r i t y ( n o r t h m r d ) B, eoents wi th the same c r i t e r i a ( 9 > 3 hrs, B , show t h a t t h e i r occurrence i s s imilar both i n number a s well a s i n t h e i r re la t ionship t o interplanetary disturbances, and th t they lead t o ZOW l e v e l s of geomagnetic cc t i v i t y .

This work t!ns p a r t i a l l ; supported by the “Fundo Nacionai de Desenvolvimento Cient i f i c o e Tecno Z6gico” under con-tract FINEP-53 7/CT. Planetary and Space Science, ntraves do J e t P r o p Zsion Laboratory.

iOnT)

- - OBSERVAC~ES/ RCMARKS - Submetido para r

l I&?€-14.