| Project/Area Number |
12640430
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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 |
Space and upper atmospheric physics
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| Research Institution | The University of Tokyo |
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Principal Investigator |
HOSHINO Masahiro Graduate School of Science, The University of Tokyo Professor, 大学院・理学系研究科, 教授 (90241257)
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| Co-Investigator(Kenkyū-buntansha) |
菅野 延枝(島田 延枝) 東京大学, 大学院・理学系研究科, 日本学術振興会 特別研究員
SUGANO Nobue (SHIMADA Nobue) Graduate School of Science, The University of Tokyo JSPS Research Fellow
菅野 延江(島田 延江) 東京大学, 大学院・理学系研究科, 日本学術振興会特別研究員
菅野 延枝 (島田 延枝) 東京大学, 大学院・理学系研究科, 日本学術振興会特別研究員
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| Project Period (FY) |
2000 – 2001
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| Project Status |
Completed (Fiscal Year 2001)
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| Budget Amount *help |
¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 2001: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 2000: ¥2,600,000 (Direct Cost: ¥2,600,000)
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| Keywords | Shock Wave / Particle Acceleration / Cosmic Ray / Numerical Simulation / Electric Solitary Wave / Shock Surfing / Surfatron Acceleration / 電子加速 / 静電ソリトン / 超新星残骸 |
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| Research Abstract |
It is known that the efficient energy transfer from ions to electron occurs in the shock transition layer, where the supersonic flow in upstream is transformed into the subsonic flow in downstream. It is also expected that the non-thermal, high-energy electron are simultaneously produced by the wave-particle interaction under the turbulence electromagnetic fields. In our study, we found the rapid energization of high-energy electron which time scale is much shorter than that for the standard diffusive/Fermi acceleration mechanism by using particle-in-cell simulations. So far the turbulent plasma waves is thought to play an important role in the shock transition layer, but it is discovered by in situ satellite observations that a large amplitude, electrostatic solitary wave is also excited in the shock transition layer. Having the solitary wave in mind, we studied how the solitary wave can be generated in the shock region, and how the solitary wave can contribute to the electron acceleration. Our new results are summarized as follows : 1) the electrostatic, solitary wave can be generated by the two-stream instability under the reflected ions from the shock and the incoming electrons in a super-critical Mach number regime, 2) some electrons can be effectively trapped by the electrostatic field through the shock surfing acceleration, which results in the formation of the nonthermal electrons, and 3) the electrons can be infinitely accelerated up to the relativistic energy if the shock Mach number exceed about several 10s. We also discussed that the electron shock surfing acceleration can be applied for the high-energy population observed in super-nova shocks as well as the interplanetary shocks.
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