2012 Fiscal Year Final Research Report
A theoretical study of magnetohydrodynamic instabilities in non-rotating and rotating magnetospheric plasmas
| Project/Area Number |
20540436
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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 | The University of Tokyo |
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Principal Investigator |
MIURA Akira 東京大学, 大学院・理学系研究科, 助教 (20126171)
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| Project Period (FY) |
2008 – 2012
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| Keywords | 磁気圏 / 電離層 / 磁気流体(MHD)不安定性 / プラズマ / 単極子磁気圏 / 双極子磁気圏 / エネルギー原理 |
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| Research Abstract |
A new magnetospheric energy principle was constructed for spherically symmetric monopolar magnetospheres with magnetic field lines extending to infinity. By using eikonal assumption, I showed the existence of ionosphere-driven magnetohydrodynamic (MHD) instabilities for spherically symmetric monopolar magnetospheres and for magnetospheres with closed field lines. For an arbitrary closed magnetospheric configuration, which includes a dipole field, a general stability criterion was obtained for pressure-driven interchange instability. A nonideal MHD eigenmode equation was derived for a velocity shear instability, which is driven by a shear in the ion diamagnetic drift velocity in sheared magnetic fields, and a general stability criterion was obtained.
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Research Products
(11 results)
