2021 Fiscal Year Final Research Report
Anisotropic mixing and dissipation processes in collisionless plasma turbulence explored in terms of fluctuation spectrum in the phase space
| Project/Area Number |
16H04086
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Plasma science
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| Research Institution | Nagoya University |
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Principal Investigator |
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| Co-Investigator(Kenkyū-buntansha) |
前山 伸也 名古屋大学, 理学研究科, 講師 (70634252)
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| Project Period (FY) |
2016-04-01 – 2021-03-31
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| Keywords | プラズマ乱流 / シミュレーション |
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| Outline of Final Research Achievements |
Before fluctuations arising in plasmas are dissipated and transformed into heat, fine structures of the electromagnetic fields and the distribution function are generated on the phase space, that consists of the real and velocity spaces, because of the low collisionality in high-temperature plasmas in space and fusion. In this study, we have analyzed turbulence in magnetized plasmas by means of numerical simulations on supercomputers and have revealed the followings. (1) Fine structures of the auroral electromagnetic fluctuations are generated through turbulence transition. (2) The velocity-space spectrum of the distribution function in the drift wave turbulence shows a power law profile. (3) A subrange with a constant transfer function of fluctuations is formed in the power spectrum, leading to universality in the formation process of fine-scale structures of the distribution function.
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| Free Research Field |
プラズマ物理学・核融合学・磁気圏物理学
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| Academic Significance and Societal Importance of the Research Achievements |
宇宙を構成する主要な物質である電離ガスをプラズマと呼ぶ。そこに現れる様々な構造や揺らぎが最終的に熱に変換されるまでにどのような過程を経るかを明らかにするための研究を実施した。その結果、プラズマ中の揺らぎには、実空間だけでなく様々な速度成分を持つ変動が発達することで効率的な散逸が起きるとともに、その分布には一定の法則性があることが明らかになった。これは宇宙空間や核融合装置でどのように熱が生まれるかという基本的な物理過程の一端を明らかにした成果といえる。
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