The Energization of Cold Ions around a Plasmoid in the Magnetotail.

• Tsubouchi Ken

  Department of Earth and Planetary Physics, University of Tokyo

• Terasawa Toshio

  Department of Earth and Planetary Physics, University of Tokyo

抄録

We study numerically the interaction of cold ionospheric ions in the tail lobe with a plasmoid propagating steadily in the tailward direction. We have found that significant energization of cold ions occurs at the encounter with a plasmoid, where three types of the interaction processes are taking place: First, ions show gradient and curvature drift motions as the plasmoid approaches. These ions are accelerated up to ∼1 keV by the cross-tail electric field accompanying with the plasmoid motion (type-I energization). Second, some of the ions get large pitch angles after the type-I acceleration, and then mirror reflected by the plasmoid. These ions are accelerated up to 10 keV after the reflection (type-II energization). Third, the motions of the ions near the plasmoid become highly non-adiabatic, because their gyroradii become comparable to the field-line curvature radius after the type-I energization. Consequently the energy distribution of these ions is broadened in the trailing side of the plasmoid (type-III energization). These theoretical results are successfully compared with the recent GEOTAIL observation showing the dynamic interaction of cold ions with a plasmoid and their subsequent energization.

収録刊行物

• Ｊｏｕｒｎａｌ　ｏｆ　ｇｅｏｍａｇｎｅｔｉｓｍ　ａｎｄ　ｇｅｏｅｌｅｃｔｒｉｃｉｔｙ

  Ｊｏｕｒｎａｌ　ｏｆ　ｇｅｏｍａｇｎｅｔｉｓｍ　ａｎｄ　ｇｅｏｅｌｅｃｔｒｉｃｉｔｙ 47 (2), 149-162, 1995

  地球電磁気・地球惑星圏学会

キーワード

• General Earth and Planetary Sciences
• General Environmental Science

詳細情報

• CRID: 1390282681486023168
• NII論文ID: 10002026380
• NII書誌ID: AA00698879
• DOI: 10.5636/jgg.47.149
• ISSN: 21855765
• ISSN: 00221392
• 本文言語コード: en
• データソース種別:
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  • CiNii Articles
• 抄録ライセンスフラグ: 使用不可