2011 Fiscal Year Final Research Report
Experimental study of the plasma acceleration/heating by large-amplitude Alfven waves in the space
| Project/Area Number |
21540465
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Space and upper atmospheric physics
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| Research Institution | Japan Aerospace Exploration Agency |
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Principal Investigator |
MATSUOKA Ayako 独立行政法人宇宙航空研究開発機構, 宇宙科学研究所, 准教授 (80270437)
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| Co-Investigator(Kenkyū-buntansha) |
TAKADA Taku 高知工業高等専門学校, 電気情報工学科, 准教授 (80455469)
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| Co-Investigator(Renkei-kenkyūsha) |
HOSHINO Masahiro 東京大学, 理学部, 教授 (90241257)
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| Project Period (FY) |
2009 – 2011
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| Keywords | 地球惑星磁気圏 |
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| Research Abstract |
Alfven waves were found to propagate toward the earth in the nightside magnetosphere. They are considered to be associated with the auroral activity at the ionospheric altitudes. We have investigated the electric and magnetic field variations measured by Geotail in the mid-tail region, 10-30 Re. We found large-amplitude electric field fluctuations and the corresponding magnetic field fluctuations having the components in the direction perpendicular to the ambient magnetic field. These fluctuations were identified as Alfven waves from the ratio between the amplitudes of electric and magnetic field. These large-amplitude Alfven waves often propagate in the direction coincides with the plasma flow, and earthward at the same time. We will further select events in which the fluctuations are identified as waves definitely. We will report the statistical result about the correspondence with the plasma properties and estimation of the energy flux carried by the Alfven waves.
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