地球の弓の衝撃の上流のエネルギーイオンの自生的で効率的な加速
D L Turner1, L B Wilson2, T Z Liu3
1Space Sciences Department, The Aerospace Corporation, El Segundo, CA, USA. drew.l.turner@aero.org.
Nature
|September 14, 2018
まとめ
地球の弓の衝撃で 熱い流れの異常が観測され 太陽風のイオンが1000キロ電子ボルト近くまで加速します この効率的なプロセスは フェルミ加速度と一致し 宇宙線注入の問題も解決するかもしれません
科学分野:
- 宇宙物理学
- プラズマ物理学
- 天体物理学
背景:
- 地球の弓の衝撃は,超音速太陽風の相互作用によって形成された衝突のない衝撃です.
- 熱流異常 (HFAs) のような一時的な現象を含んでいる.
- HFAsは衝撃反射イオンの濃度であり,潜在的に加速する粒子です.
研究 の 目的:
- 熱流の異常の中で粒子の加速を観察し,特徴づけること.
- HFAによる粒子加速のメカニズムを調査する
- HFAのエネルギー粒子生成への貢献を評価する.
主な方法:
- ホット・フロー・アノマリー・イベントの 現場観測
- 太陽風のイオン特性とエネルギースペクトルの分析
- 第1次フェルミ加速モデルとの比較
主要な成果:
- 観測された太陽風イオンは,HFA内で1-10 keVから約1,000 keVまで加速した.
- 加速効率はイオン質量と電荷状態に依存する.
- HFAsは典型的な弓の衝撃加速よりもはるかにエネルギーのある粒子を生成します.
結論:
- 準平行な弓の衝撃で HFA は非常に効率的な粒子加速器です.
- このメカニズムは 宇宙線の"インジェクション問題"に 潜在的な解決策を提供します
- フロームストックトランジエントは,天体物理的な衝撃でエネルギー粒子を生成する上で重要な役割を果たす可能性があります.
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