| Project/Area Number |
10680468
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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 |
プラズマ理工学
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| Research Institution | National Institute for Fusion Science |
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Principal Investigator |
HORIUCHI Ritoku National Institute for Fusion Sciences, Theory and Computer Simulation Center, Professor, 理論・シミュレーション研究センター, 教授 (00229220)
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| Co-Investigator(Kenkyū-buntansha) |
TAKAMARU Hisanori National Institute for Fusion Sciences, Theory and Computer Simulation Center, Assistant Professor, 理論・シミュレーション研究センター, 助手 (20241234)
WATANABE Tomohiko National Institute for Fusion Sciences, Theory and Computer Simulation Center, Assistant Professor, 理論・シミュレーション研究センター, 助手 (30260053)
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| Project Period (FY) |
1998 – 1999
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| Project Status |
Completed (Fiscal Year 1999)
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| Budget Amount *help |
¥1,300,000 (Direct Cost: ¥1,300,000)
Fiscal Year 1999: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1998: ¥700,000 (Direct Cost: ¥700,000)
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| Keywords | collisionless plasma / magnetic reconnection / particle simulation / anomalous resistivity / particle kinetic effect / ion Larmor radius / drift-kink instability / anomalous ion heating / 非等方イオン加熱 / プラズマ不安定性 / 外部駆動電場 / 波粒子相互作用 |
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| Research Abstract |
Triggering mechanism of magnetic reconnection in a collisionless plasma is investigated by means of three-dimensional electromagnetic particle simulation. Main results are summarized as follows.
A. There exist two types of triggering mechanisms which break the frozen-in condition of magnetic field and lead to magnetic reconnection in a collisionless plasma. One is due to the wave-particle interaction which is a cause of anomalous resistivity in the current sheet. The other is due to the particle kinetic effect which becomes significant in a particle scale such as an electron collisionless skin depth and an ion Larmor radius.
B. When there is not any driving source, two kinds of plasma instabilities grow in the current layer, I.e., the lower hybrid drift instability (LHDI) and the drift kink instability (DKI) instability. The LHDI grows in the periphery of the current layer, but it can not penetrate into a high beta region in the vicinity of the neutral sheet. The DKI is excited near the neutral sheet in a late period as a result of the nonlinear deformation of the current sheet by the LHDI, and can be a cause of anomalous resistivity, leading to collisionless reconnection at the neutral sheet.
C. When an external driving field exists, the convective electric field penetrates into the current layer through the particle kinetic effect and collisionless reconnection is triggered by the convective electric field earlier than the DKI is excited. The growth rate of the DKI becomes larger compared with no driving field case, due to the compression of current layer by the convergent plasma flow.
D. The anisotropic ion distribution is formed through the anomalous ion heating by the DKI.
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