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強いプラズマ波が太陽風の近くで発生し,太陽風の衝撃を終わらせる
1Department of Physics and Astronomy, University of Iowa, Iowa City, Iowa 52242, USA. donald-gurnett@uiowa.edu
Nature
|July 4, 2008
まとめ
ヴォイジャー2号は,太陽風の終結ショックで激しいプラズマ波を検出しました. これらの電場は,惑星の弓の衝撃に類似しており,エネルギー分散と粒子の再均衡に不可欠です.
科学分野:
- 宇宙物理学 宇宙物理学
- プラズマ物理学 プラズマ物理学
- ヘリオフィジックス ヘリオフィジックス
背景:
- プラズマ波は,衝撃移行層における非熱粒子分布によって生成されます.
- これらの波の電場は,衝撃エネルギーの消散と粒子の熱化において重要な役割を果たします.
研究 の 目的:
- 太陽風の終電ショックで強いプラズマ波の電場が検出されたことを報告します.
- これらの波の性質を特徴付け,他の天体物理的な衝撃における同様の現象と比較する.
主な方法:
- "ボイジャー2"宇宙船のプラズマ波装置を利用した.
- アップストリーム電子プラズマ振動とブロードバンド静電波の爆発に関するデータを分析した.
主要な成果:
- 2007年8月1日から83.4天文単位 (au) で,上流の電子プラズマ振動が検出されました.
- 2007年8月31日から9月1日の83.7 AUの間の終端ショッククロスで,ブロードバンド静電波の激しい爆発が観測されました.
- 波のスペクトルは,惑星の弓の衝撃で観測されたものと同等であることが判明しました.
結論:
- 検出された波は,太陽風の終結ショックで強い電場があることの直接的な証拠を提供します.
- 惑星の弓の衝撃波との類似性は,異なるプラズマ環境における衝撃相互作用を支配する共通の物理的プロセスを示唆しています.
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