HR: 0800h
AN: SH41A-0300    [Abstracts]
TI: Toward a better understanding on particle acceleration in solar flares within the framework of the GEMSIS project
AU: * Masuda, S
EM: masuda@stelab.nagoya-u.ac.jp
AF: Solar-Terrestrial Environment Laboratory, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 4648601, Japan
AU: Inoue, S
EM: inosato@stelab.nagoya-u.ac.jp
AF: Solar-Terrestrial Environment Laboratory, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 4648601, Japan
AB: GEMSIS (Geospace Environment Modeling System for Integrated Studies) is one of projects in Solar-Terrestrial Environment Laboratory, Nagoya University. Its final goal is to build a geospace-environment model based on various (satellite and ground-based) observational facts in order to understand the dynamic energy-transport- processes taking place in geospace. In the first 3-years from this year, we set a few individual scientific targets as fundamental elements/information for the final model. One of them is to know how the accelerated particles are accelerated and lose their energies in solar flares. Here, we briefly introduce our approach to this scientific target. Thanks to Yohkoh and RHESSI observations, some essentials (energy spectrum of accelerated electrons, acceleration site, time-scale of acceleration) for revealing the acceleration mechanism are somehow obtained. However, we don"t have any direct observations about pitch-angle distribution of accelerated electrons even though it is important information to identify the acceleration mechanism. In some flares, most of accelerated electrons are trapped in a magnetic loop system, and stay in the loop for a few minutes until they precipitate into the footpoint region due to pitch-angle scattering via collision. At that time, hard X-ray thin-target emission and microwave gyrosynchrotron emissions from trapped electrons are observed in the corona and mainly hard X-ray thick target emissions are observed at the footpoint region. The temporal behavior of spectrum and intensity of each source depends on the initial pitch-angle distribution of accelerated electrons. However, it also depends on other two parameters, i.e., the magnetic mirror efficiency and the plasma density in the loop. First we must determine these two parameters. In this paper, some preliminary results are introduced.
DE: 7509 Corona
DE: 7519 Flares
DE: 7524 Magnetic fields
DE: 7534 Radio emissions
DE: 7554 X-rays, gamma rays, and neutrinos
SC: SPA-Solar and Heliospheric Physics [SH]
MN: 2007 Fall Meeting