HR: 1340h
AN: SH13A-0292 [Abstracts]
TI: Solar neutron events associated with large solar flares in solar cycle 23
AU: * Watanabe, K
EM: kwatana@stelab.nagoya-u.ac.jp
AF: Solar-Terrestrial Environment Laboratory, Nagoya University, Nagoya, 464-8601
Japan
AU: Muraki, Y
EM: muraki@stelab.nagoya-u.ac.jp
AF: Solar-Terrestrial Environment Laboratory, Nagoya University, Nagoya, 464-8601
Japan
AU: Matsubara, Y
EM: ymatsu@stelab.nagoya-u.ac.jp
AF: Solar-Terrestrial Environment Laboratory, Nagoya University, Nagoya, 464-8601
Japan
AU: Sako, T
EM: sako@stelab.nagoya-u.ac.jp
AF: Solar-Terrestrial Environment Laboratory, Nagoya University, Nagoya, 464-8601
Japan
AU: Masuda, S
EM: masuda@stelab.nagoya-u.ac.jp
AF: Solar-Terrestrial Environment Laboratory, Nagoya University, Nagoya, 464-8601
Japan
AU: Sakai, T
EM: tsakai@cit.nihon-u.ac.jp
AF: College of Industrial Technologies, Nihon University, Narashino, 275-0005
Japan
AU: Tsuchiya, H
EM: htsuchiya@postman.riken.jp
AF: RIKEN, Wako, Saitama, 351-0198
Japan
AU: Shibata, S
EM: shibata@isc.chubu.ac.jp
AF: College of Engineering, Chubu University, Kasugai, 487-8501
Japan
AU: Yoshimori, M
EM: yosimori@rikkyo.ac.jp
AF: Department of Physics, Rikkoyo University, Toshima-ku, Tokyo, 171-8501
Japan
AU: Ohmori, N
EM: ohmori@cc.kochi-u.ac.jp
AF: Department of Physics, Kochi University, Kochi, 780-8520
Japan
AU: Velarde, A
EM: avelarde@fiumsa.edu.bo
AF: Instituto Investigaciones Fisicas, Universidad Mayor de San Andrés, La Paz, 000
Bolivia
AU: Ticona, R
EM: rticona@umsanet.edu.bo
AF: Instituto Investigaciones Fisicas, Universidad Mayor de San Andrés, La Paz, 000
Bolivia
AU: Martinic, N
EM: martinic@acelerate.com
AF: Instituto Investigaciones Fisicas, Universidad Mayor de San Andrés, La Paz, 000
Bolivia
AU: Miranda, P
EM: -
AF: Instituto Investigaciones Fisicas, Universidad Mayor de San Andrés, La Paz, 000
Bolivia
AU: Kakimoto, F
EM: kakimoto@cr.phys.titech.ac.jp
AF: Department of Physics, Tokyo Institute of Technology, Meguro-ku, Tokyo, 152-8551
Japan
AU: Ogio, S
EM: sogio@cr.phys.titech.ac.jp
AF: Graduate School of Science, Osaka City University, Osaka, 558-8585
Japan
AU: Tsunesada, Y
EM: y.tsunesada@nao.ac.jp
AF: Department of Physics, Tokyo Institute of Technology, Meguro-ku, Tokyo, 152-8551
Japan
AU: Tokuno, H
EM: htokunou@cr.phys.titech.ac.jp
AF: Department of Physics, Tokyo Institute of Technology, Meguro-ku, Tokyo, 152-8551
Japan
AU: Shirasaki, Y
EM: yuji.shirasaki@nao.ac.jp
AF: RIKEN, Wako, Saitama, 351-0198
Japan
AU: Valdés-Galicia, J F
EM: jfvaldes@geofisica.unam.mx
AF: Instituto de Geofísica, Universidad Nacional Autónoma de México, D. F. México, 04510
Mexico
AU: Hurtado, A
EM: -
AF: Instituto de Geofísica, Universidad Nacional Autónoma de México, D. F. México, 04510
Mexico
AU: Musalem, O
EM: -
AF: Instituto de Geofísica, Universidad Nacional Autónoma de México, D. F. México, 04510
Mexico
AU: Ogasawara, R
EM: ryu@subaru.naoj.org
AF: National Astronomical Observatory of Japan, Hilo, Hawaii, 96720
United States
AU: Mizumoto, Y
EM: mizumoto.y@nao.ac.jp
AF: National Astronomical Observatory of Japan, Hilo, Hawaii, 96720
United States
AU: Nakagiri, M
EM: nakagiri@solar.mtk.nao.ac.jp
AF: National Astronomical Observatory of Japan, Hilo, Hawaii, 96720
United States
AU: Miyasita, A
EM: miyasita@hotaka.mtk.nao.ac.jp
AF: National Astronomical Observatory of Japan, Hilo, Hawaii, 96720
United States
AU: Stoker, P H
EM: FSKPHS@puknet.puk.ac.za
AF: School of Physics, Potchefstroom University, Potchefstroom, 000
South Africa
AU: Lopate, C
EM: lopate@ulysses.sr.unh.edu
AF: The University of New Hampshire, Space Science Center, New Hampshire, 03824
United States
AU: Kudela, K
EM: kkudela@upjs.sk
AF: Institute of Experimental Physics, SAS, Kosice, 000
Slovakia (Slovak Republic)
AU: Gros, M
EM: MGROS@DAPNIA.CEA.FR
AF: DSM/DAPNIA/SAp, CEA Saclay, Gif-sur-Yvette, 91191
France
AB:
We have investigated ion acceleration mechanisms in solar flares by observing solar neutrons produced by in association with
these solar flares. Solar neutrons are observed by means of ground-based neutron monitors and solar neutron telescopes which
form an international network for solar neutron observations. Observations of solar neutrons have been made during solar
cycle 23 using this network.
More than a hundred X class flares have been recorded in solar cycle 23. Corresponding to these, five solar neutron events
were observed by ground-based neutron monitors from the flares of November 24, 2000, August 25, 2001, October 28, November 2
and 4, 2003. The statistical significances of all these events were, very significant (more than 5 σ), and the
excesses were clear.
These solar neutron events observed in solar cycle 23 were detected in association with strong emissions of hard X-rays and
γ -rays. The occurrence of solar neutrons appears to be correlated with the intensity of hard X-rays and γ
-rays emitted by the associated solar flare as observed by the Yohkoh, RHESSI and INTEGRAL satellites.
Assuming that solar neutrons are produced at the same time as the emission of these γ -rays, a good correlation is
found between the production times of solar neutrons and the observed excesses of neutron monitors. The corresponding energy
spectra of solar neutrons at the solar surface is well described by a power law. The spectral indexes of the solar neutron
events we have observed in solar cycle 23 are typical for the solar neutron events observed so far, being between -3 and
-4, although the fluxes are fainter than those observed in earlier events. From the spectra of solar neutrons, the energy
spectra of accelerated ions can be deduced and these are found to be softer than the neutron spectra, which have spectral
indexes between -4 and -5. The corresponding number of protons above 30 MeV was estimated to be between
1030 and 1033 for these events.
DE: 7500 SOLAR PHYSICS, ASTROPHYSICS, AND ASTRONOMY
DE: 7514 Energetic particles (2114)
DE: 7519 Flares
DE: 7554 X-rays, gamma rays, and neutrinos
SC: SPA-Solar and Heliospheric Physics [SH]
MN: Fall Meeting 2005