Impact of substorm time O<sup>+</sup> outflow on ring current enhancement
書誌事項
- タイトル別名
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- Impact of substorm time O⁺ outflow on ring current enhancement
抄録
Energetic O⁺ ions (tens of keV) rapidly increase in the inner magnetosphere and contribute significantly to the ring current during substorms. Previously, two source regions of the energetic O⁺ ions have been proposed. The first one is the dayside polar region. Ions from the dayside polar region are transported to the lobe; then they are injected to the nightside plasma sheet during substorm expansion phase. The second one is the nightside aurora region. After the substorm onset, energetic O⁺ ions are extracted from the ionosphere with the auroral acceleration processes, and the O⁺ ions are directly supplied to the nightside plasma sheet. We investigated the relative importance of these two regions on supplying the energetic O⁺ ions in the inner magnetosphere. We performed a test particle simulation in global MHD electromagnetic fields. We obtained the following results. (1) During the substorm growth phase, O⁺ ions at tens of eV are extracted from the dayside polar region, resulting in the enhancement of the warm O⁺ ions (hundreds of eV) in the lobe. After the substorm onset, the warm O⁺ ions are nonadiabatically accelerated to tens of keV and injected to the inner magnetosphere. These O⁺ ions contribute to most of the O⁺ ring current. (2) O⁺ ions at < a few keVs are supplied from the nightside aurora region to the plasma sheet. However, their contribution to the O⁺ ring current remains small. From the results, we concluded that the main source of the energetic O⁺ ions is the dayside polar region.
収録刊行物
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- Journal of Geophysical Research: Space Physics
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Journal of Geophysical Research: Space Physics 122 (6), 6304-6317, 2017-06
American Geophysical Union (AGU)
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詳細情報 詳細情報について
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- CRID
- 1050291037075022080
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- NII論文ID
- 120007187511
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- ISSN
- 21699402
- 21699380
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- HANDLE
- 2433/267741
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- 本文言語コード
- en
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- 資料種別
- journal article
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- データソース種別
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