波のグローバル形態論 ポインティングの流れ:オーロラを動かす
A Keiling1, J R Wygant, C A Cattell
1Department of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55144, USA. akeiling@ham.space.umn.edu
Science (New York, N.Y.)
|January 18, 2003
まとめ
グローバルなアルフヴェン波は,電磁波の一種で,地球の極光に重要なエネルギーを供給します. この発見は,これらの素晴らしい光ディスプレイを動かすエネルギー源についての私たちの理解を広げています.
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
- 大気科学 大気科学
背景:
- オーロラは,主に磁場線に沿って地球の極地へと流れる電流に起因する.
- イオノスフィアのオーロラを動かす精密なエネルギー転送機構はまだ調査中です.
研究 の 目的:
- 電磁波,特にアルフヴェン波が,オーロラエネルギーに与える潜在的世界的な貢献を調査する.
- 高海拔のアルフヴェン波が,オーロラ加速プロセスを十分に動かすことができるかどうかを判断する.
主な方法:
- 極地宇宙船が1年間にわたって収集したデータの分析.
- 25,000~38,000キロメートルの高さでポイントリング流 (波電磁気エネルギー流) を測定する.
- エネルギーフローと統計的なオーロラ・オーバルとの相関関係.
主要な成果:
- 電磁波 (アルフヴェン波) による地球規模の貢献の証拠が見つかりました.
- 高地における電磁波エネルギーの流れは,統計的なオーロラ・オーバルを線引きする.
- 個々のイベントのポインティングフロースは5ergs/cm2/sを超え,オーロラ加速には十分である.
結論:
- アルフヴェン波は,昼と夜の両方のオーロラにとって重要な世界的なエネルギー源を表しています.
- この発見は,オーロラに二重のエネルギー源があることを示唆している:磁場に整合した電流と,高空のアルフヴェン波である.
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