星間境界探査機によって観測された ENA 流動リボンの幅と変動
S A Fuselier1, F Allegrini, H O Funsten
1Lockheed Martin Advanced Technology Center, Palo Alto, CA 94304, USA. stephen.a.fuselier@lmco.com
Science (New York, N.Y.)
|October 17, 2009
まとめ
星間境界探査機 (IBEX) のミッションは,エネルギー中性原子 (ENA) の流動の顕著なリボンを明らかにしました. 太陽風とイオン集団の増強によって引き起こされる可能性が高いこのリボンは,ヘリオシートの中心的な特徴です.
科学分野:
- 宇宙物理学 宇宙物理学
- ヘリオフィジックス ヘリオフィジックス
- 天体物理学 天体物理学
背景:
- ヘリオスフィアは,太陽風によって作られた巨大なプラズマの泡で,惑星を超えて広がっています.
- エネルギー中性原子 (ENAs) は,直接測定ではアクセスできない,遠くのヘリオスフィアに関する重要な情報を提供します.
- 星間境界探査機 (IBEX) のミッションは,恒星間介質とヘリオスフィアの相互作用を研究するために,ENAの放射をマッピングします.
研究 の 目的:
- IBEX ENAの空の地図で観察された支配的なリボン特徴の特徴を分析する.
- ヘリオスフィアのENAリボンのエネルギー依存性と空間的範囲を決定する.
- リボン内の強化された ENA 流れの潜在的な起源を調査する.
主な方法:
- 星間境界探査機 (IBEX) の衛星データの分析.
- 空を横断するエネルギー中性原子 (ENA) の流れのマッピング.
- ENA流量強度とリボン特性 (幅,経度,緯度) の定量評価.
主要な成果:
- 強化された ENA 流れの支配的なリボン特徴は,IBEX スカイマップで特定されました.
- リボンは長度300度を超え,平均幅は約20度である.
- リボン内の ENA 流は,拡散した ENA 背景の 2 ~ 3 倍であり, ~ 1 keV で最も顕著です.
結論:
- ヘリオスフィアのENAリボンは,ヘリオスフィアの持続的で重要な特徴です.
- その特徴は,強化された太陽風と,ヘリオシート内のピックアップイオン集団に関連した起源を示唆しています.
- リボンのさらなる研究は,ヘリオスフィアの境界過程を理解するために不可欠です.
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