1997 Fiscal Year Final Research Report Summary
Study on collision between a current loop and a plasma cloud in solar flares
| Project/Area Number |
07640352
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Astronomy
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| Research Institution | Toyama University |
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Principal Investigator |
SAKAI Jun-ichi Toyama University, Faculty of Engineering, Professor, 工学部, 教授 (50019220)
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| Project Period (FY) |
1995 – 1997
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| Keywords | solar flare / Current loop / Particle Acceleration |
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| Research Abstract |
One of important unsolved problems in Plasma Astrophysics is how the magnetic field energy released during a solar flare can be converted to plasma heating as well as high energy particle acceleration.
A new flare observed by the YOHKOH sattelite, which is so called as Masuda-flare showed a loop structure in the soft X-ray image with hard X-ray source, which location is just above the soft X-ray loop top. To explain this flare, Masuda et al.proposed a model that this flare was caused by the interaction between a current loop and a plasmoi(plasma cloud).
(1) In order to explain the X-ray source observed in this flare, we investigated the collision process between a current loop and a plasma cloud by using 3-D MHD code and 3-D particle code, and made clear the plasma heating process and the mechanism of high energy electron acceleration.
(2) We investigated the coalescence process of X-type current loop collision by 3-D MHD simulation and compared with a typical X-type flare on the 1993, Aug.2. The result showed a good agreement on the temperature variation between the observation and the simulation.
(3) The recombination effect becomes important for the reconnection process in the chromosphere. This effect was investigated by the MHD simulation with recombination effect. It has been shown that the recombination effect greatly enhances the plasma heating during the magnetic reconnection in the chromosphere.
(4) The nonlinear behavior of Alfven waves in weakly ionized plasmas was investigated and it was shown that the modulational instability of the Alfven waves is important for the local plasma heating. The results were applied to the solar chromospheric heating.
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