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磁気再接続のX線は,太陽風の太陽風で390以上の地球半径を広げています
T D Phan1, J T Gosling, M S Davis
1Space Sciences Laboratory, University of California, Berkeley, California 94720, USA. phan@ssl.berkeley.edu
Nature
|January 13, 2006
まとめ
エネルギー変換に不可欠な磁気再接続は,本質的に不整なプロセスではなく,大規模なプロセスであることが示されています. この発見は,宇宙環境における磁気再接続に関する以前の仮定に異議を唱える.
科学分野:
- プラズマ物理学のプラズマ物理学
- 宇宙物理学の宇宙物理学
- 天体物理学 天体物理学
背景:
- 磁気再接続は,磁気エネルギーを粒子エネルギーに変換し,様々な自然環境や実験室で不可欠です.
- 磁気再接続の規模 (パッチ対拡張) は,まだ未解決の重要な問題である.
- 地球の磁気圏での観測は,局所的で不規則な再接続を示唆しています.
研究 の 目的:
- 磁気再接続の基本的なスケールを調査する.
- 再接続が本質的に不規則なのか,それとも大規模な現象なのかを判断する.
- 磁気再接続が起こる条件を理解する.
主な方法:
- 3つの宇宙船の観測を活用して,磁気再接続中の加速した流れを分析した.
- 太陽風の流れに埋め込まれた電流シート内の再接続イベントを調べた.
- 統計的有意性を確立するために28の異なる再接続イベントを分析しました.
主要な成果:
- 再接続のX線が少なくとも390地球の半径 (2.5×10^6 km) に及ぶことが観測されました.
- 証拠によると,磁気再接続は基本的に大規模なプロセスである.
- 再接続は,外部ドライビングフローがない場合でも,準安定状態で発生することができます.
結論:
- 磁気再接続は,ある磁気圏観測とは対照的に,主に大規模なプロセスである.
- 地球の磁気圏における断片的な再接続は,固有の特性ではなく,境界条件によるものである可能性が高い.
- 再接続は,外部フローダイナミクスから独立して,ほぼ安定して動作することができます.
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