The Structure of the Plasma Sheet and Its Boundary Layers.

• Onsager T. G.

  Space Science Center and Department of Physics, University of New Hampshire Now at: NOAA Space Environment Center

• Mukai T.

  Institute of Space and Astronautical Science

書誌事項

タイトル別名

• Structure of the Plasma Sheet and Its B

抄録

Spacecraft observations made at low-altitudes in the nightside auroral region and also farther downtail in the plasma sheet and plasma sheet boundary layer typically exhibit distinctive features in the electron and ion fluxes. At low altitudes, spacecraft often detect velocity-dispersed ion beams, auroral arcs, and a region showing a localized absence in the precipitating ion flux (called the gap). Farther downtail, for example at X_GSM ≈ -15 R_E, spacecraft detect features such as an offset between the electron and ion layers of the plasma sheet boundary layer, field-aligned ion beams, and the evolution of the ion beams to isotropic distributions. Using a 3-D model of electron and ion distributions throughout the magnetotail, we have estimated the spatial relationship between these various features at low and high altitudes and the properties of the downtail plasma sheet that correspond to these small-scale structures. Consistent with previous results, we find that the velocity-dispersed ion structure observed at low altitudes corresponds to the field-aligned ion beams observed farther downtail in the plasma sheet boundary layer. Contrary to previous suggestions, we find that the gap, and therefore the co-located auroral arcs, does not map to the near-Earth plasma sheet. Our results indicate that the gap maps to the location in the plasma sheet boundary layer where the transition is occurring between the field-aligned ion beams and the more isotropic distributions characteristic of the central plasma sheet. In the distant tail neutral sheet, this region maps to where the earthward convection velocity is in transition from high values, just inside the distant reconnection site, to slower values somewhat nearer the Earth.

収録刊行物

• Ｊｏｕｒｎａｌ　ｏｆ　ｇｅｏｍａｇｎｅｔｉｓｍ　ａｎｄ　ｇｅｏｅｌｅｃｔｒｉｃｉｔｙ

  Ｊｏｕｒｎａｌ　ｏｆ　ｇｅｏｍａｇｎｅｔｉｓｍ　ａｎｄ　ｇｅｏｅｌｅｃｔｒｉｃｉｔｙ 48 (5/6), 687-697, 1996

  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: 1390001206510564480
• NII論文ID: 130003559420
• NII論文ID: 10002403472
• NII書誌ID: AA00698879
• DOI: 10.5636/jgg.48.687
• ISSN: 21855765
• ISSN: 00221392
• NDL書誌ID: 4060365
• Web Site: https://ndlsearch.ndl.go.jp/books/R000000004-I4060365
• 本文言語コード: en
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