Search for solar neutrons associated with proton flares in solar cycl
e 23
Yutaka Matsubara (presenter)Solar-Terrestrial Environment Laboratory,
Nagoya University
August, 2005, Pune29th International Cosmic Ray Conference
Authors
Y. Matsubara1, Y. Muraki1, T. Sako1, K. Watanabe1, S. Masuda1, T. Sakai2, S. Shibata3, E. Flückiger4, R. Bütikofer4, A. Chilingarian5, G. Hovsepyan5, Y. H. Tan6, T. Yuda7, M. Ohnishi7, H. Tsuchiya8, Y. Katayose9, R. Ogasawara10, Y. Mizumoto10, M. Nakagiri10, A. Miyashita10, A. Velarde11, R. Ticona11, and N. Martinic11
(1) Solar-Terrestrial Environment Laboratory, Nagoya University(2) College of Industrial Technologies, Nihon University(3) College of Engineering, Chubu University(4) Physikalisches Institut, University of Bern(5) Yerevan Physics Institute(6) Institute of High Energy Physics, Chinese Academy of Scienc
e(7) Institute for Cosmic Ray Research, University of Tokyo(8) RIKEN(9) Facaulty of Engineering, Yokohama National University(10) National Astronomical Observatory of Japan(11) Institoto de Investigaciones Fisicas, Universidad Mayor de San Andres
Contents
1. Motivation
2. Solar neutron telescopes
3. Solar neutrons associated
with proton flares
4. Summary
1. Motivation
Soft X-rays versus Protons
S12W83X-class
proton
Aug17 Aug18 Aug19 Apr10 Apr11 Apr12
2004
S14W47
Soft X-rays versus Protons
Jul26 Jul27 Jul28
2005
East limb
Where do these protons come from ?
X-class flares without protons
971127 1259 X 2.6 2B N17E63 8113980818 2210 X 4.9 1B N33E87 8307010825 1623 X 5.3 3B S17E34 9591011213 1420 X 6.2 3B N16E 9 9733020520 1521 X 2.1 2N S21E65 9961020703 208 X 1.5 1B S20W51 17020723 18 X 4.8 2B S13E72 39020830 1247 X 1.5 SN N15E74 95030611 2001 X 1.6 1N N14W59 375031103 943 X 3.9 2F N 8W77 488040716 1349 X 3.6 3B S11E35 649040818 1729 X 1.8 SF S12W83 656
What do we search for ?
To detect solar neutrons: in the past→We investigated large flares in X-rays
To detect solar neutrons: in this work→We investigate proton flares
2. Solar neutron telescopes
World-wide Solar Neutron Telescopes
Summary of solar neutron telescopes
Solar neutron telescopes are at good places to observe high energy protons !
Typical Solar Neutron Telescope
n
p
3. Solar neutrons associated with proton flares
GLE: April 2001
Oulu: April 2001
Cou
nti
ng
rate
incr
ease
(%
)
40
0
April 18, 2001
GOES Soft-X
>10MeV
>50MeV >100MeV
3 days
Proton
Apr17 Apr18 Apr19
X-class
Oulu: 010418
>10% increase around 3 UT
GOES Proton vs Neutron Monitor: 010418
39 - 82MeV
Oulu(0.8GV)
84 - 200MeV
110 - 500MeV
Higher energy channels increase more rapidly than lower energy channels !
Positionof the Sun
0104183:30 UT
Norikura vs Tibet: 010418
Norikura >20MeV
Tibet >40MeV
Both increse around the same time as Oulu
Norikura vs Oulu vs Goes-p: 010418
Norikura (>20MeV)
Oulu(0.8GV)
GOES-p(110 - 500MeV)
Norikura increased later than others
[ Expected ]
neutron>Oulu>GOES-proton
[ Obtained ]
Oulu>GOES-proton>neutron
The Gornergrat and Aragats stations (night) also show increases !!!
010418 (Norikura, Tibet, Gornergra, Aragats)
Norikura >20MeV Tibet >40MeV
Gornergrat >40MeV Armenia >40MeV
4. Summary
Several solar neutron telescopes show similar time profiles of counting rates on
・ March 31, 2001
・ April 15, 2001 (GLE event)
・ April 18, 2001 (GLE event)
・ October 29, 2003 (GLE event)
・・・・・・At the moment, no indication of solar neutrons has been detected, but……
Summary
・ Solar neutrons have been searched for associated with proton flares by using solar neutron telescopes.
(also high energy protons)
・ So far, only indications of high energy protons have been accumulated.
This study is in progress for events obtained during Solar Cycle 23.
EndEnd
Thank you very much for your attention !Thank you very much for your attention !
List of Ground Level EnhancementNovember 6, 1997 X9.4May 2, 1998 X1.1August 24, 1998 X1.0June 14, 2000 X5.7April 15, 2001 X14.0April 18, 2001 M1.3???November 4, 2001 X1.0 December 26, 2001 M7.1August 24, 2002 X3.1October 28, 2003 X17.0October 29, 2003 X10.0January 20, 2005 X7.1
byOulu NM
Neutrons are attenuated in the air1. Solar neutron telescopes should be
at high mountains.
near the equator.
for charged particles: opposite
2. Solar neutron telescopes should be operated
at different longitudes.
Location of neutron monitors
1
10
1
10
Solar neutron telescope can
1. measure energy of neutrons (nm: weak)
2. measure direction of neutrons (nm: never)
3. discriminate neutrons from protons (nm: never)
Understanding from solar neutron telescopes
Time and duration of neutron production
Total energy of high energy neutrons
Relation between neutron observation and flare position
Acceleration time of ions
Efficiency of acceleration
Direction of acceleration
Directly connected with ion acceleration
Observation Acceleration model
Ground Level Enhancement: 000714
15%
July 2000
14 日
July 14, 2000
GOESSoft-X
Proton>10MeV
X5.7
>50MeV
>100MeV
3 days
Jul13 Jul14 Jul15
X-class
GOES X-ray vs Proton
40 - 80MeVX-ray
80 - 165MeV
165 - 500MeV
Soft X-rays started earlier than protons
GOES Proton vs Neutron Monitor
40 - 80MeV
NM: Apatity(0.65GV)
80 - 165MeV
165 - 500MeV
Higher energy channels increase more rapidly than lower energy channels
GOES vs Neutron Monitor: 000714
X-ray
Apatity
165 - 500MeV
Start time of increase of counting rate:(1) X (2) NM (3) GOES-proton
March 31, 2001
GOESSoft-X
>10MeV
>50MeV
>100MeV3 days
Proton
Mar30 Mar31 Apr1
X-class
Norikura vs Tibet vs Goes-p: 010331
Norikura (>20MeV)
GOES-p(10 - 40MeV)
Norikura & Tibet increase later than GOES-p
Tibet (>40MeV)
010331 (Norikura, Tibet, Gornergra, Aragats)
Norikura >20MeV Tibet >40MeV
Gornergrat >40MeV Armenia >40MeV
April 15, 2001
GOES
Soft-X
>10MeV
>50MeV >100MeV
3 days
Proton
Apr14 Apr15 Apr16
X-class
Gornergrat vs Oulu vs Goes-p: 010415
Oulu(0.8GV)
GOES-p(84 - 200MeV)
Gornergrat increased most rapidly
Gornergrat(>40MeV)
010415 (Norikura, Gornergrat, Aragats)
Norikura >20MeV
Gornergrat >40MeV Armenia >40MeV
June 18, 2003
GOES
Soft-X
>10MeV>50MeV
>100MeV3 days
Proton
Jun17 Jun18 Jun19
X-class
Oct 29, 2003
GOES
Soft-X
>10MeV>50MeV
>100MeV
3 days
Proton
Oct28 Oct29 Oct30
X-class
Gorner. vs Nor. vs Oulu vs Goes-p: 031029
Oulu(0.8GV)
GOES-p (15-40MeV)
Gornergrat and GOES-p behave similarly
Gornergrat (>40MeV)Norikura >20MeV
031029 (Norikura, Tibet, Gornergrat, Aragats)
Norikura >20MeV
Gornergrat >40MeV Armenia >40MeV
Tibet >40MeV
List of >M flare around 010418
010409 1520 M 7.9 2B S21W04 9415 010410 0506 X 2.3 3B S23W09 9415 010411 1256 M 2.3 1F S22W27 9415 010412 0256 M 1.3 1N S22W38 9415 010412 0939 X 2.0 SF S19W43 9415 010414 1715 M 1.0 SF S16W71 9415 010415 1319 X 14.0 2B S20W85 9415 010420 0501 M 1.0 1F N16E63 9433 010420 1951 M 4.1 1F N15E55 9433 010422 2037 M 3.2 1N N14E18 9433 010423 0119 M 1.0 1F N18E18 9433 010423 2015 M 4.0 2N N14E23 9433 010424 0533 M 2.1 1N N18E01 9433