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Simulation of Kelvin-Helmholtz Instability at the Magnetospheric Boundary
http://hdl.handle.net/2261/38130
http://hdl.handle.net/2261/3813063e32167-f315-47b4-918e-66e80955c36c
| 名前 / ファイル | ライセンス | アクション |
|---|---|---|
JGR_A092_NA04_03195.pdf (1.2 MB)
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| Item type | 学術雑誌論文 / Journal Article(1) | |||||
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| 公開日 | 2010-11-18 | |||||
| タイトル | ||||||
| タイトル | Simulation of Kelvin-Helmholtz Instability at the Magnetospheric Boundary | |||||
| 言語 | ||||||
| 言語 | eng | |||||
| 資源タイプ | ||||||
| 資源 | http://purl.org/coar/resource_type/c_6501 | |||||
| タイプ | journal article | |||||
| 著者 |
Miura, Akira
× Miura, Akira |
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| 著者所属 | ||||||
| 著者所属 | Geophysics Research Laboratory, University of Tokyo | |||||
| 抄録 | ||||||
| 内容記述タイプ | Abstract | |||||
| 内容記述 | A two-dimensional magnetohydrodynamic simulation of Kelvin-Helmholtz instability at the terrestrial magnetospheric boundary is performed by including gradients of plasma and magnetic field normal to the dayside low-latitude magnetospheric boundary. A magnetopause current layer is corrugated highly nonlinearly by the instability, and a plasma blob is formed by an interchange motion associated with the instability. The magnetosheath plasma flow momentum is diffused into the magnetosphere by the anomalous tangential (Reynolds plus Maxwell) stresses associated with the instability, and a wide velocity boundary layer is formed just inside the magnetopause current layer, while the thickness of the magnetopause current layer remains almost constant during the evolution of the instability. The convection voltage drop (integral of the convection electric field) across the velocity shear layer is amplified several times by the anomalous momentum transport associated with the instability. The anomalous momentum flux into the magnetosphere (tangential stress) reaches 0.6 to a few percent of the magnetosheath flow momentum flux, and this anomalous momentum flux into the magnetosphere is sufficient for accounting for the observed tailward momentum flux in the low-latitude boundary layer. The value of the anomalous viscosity νano depends importantly on the magnetosheath Alfvén Mach number MA , which is defined by a magnetosheath magnetic field component parallel to the magnetosheath flow velocity; for MA = 2.5,νano is equal to ∼ 0.014 × 2aV0 , where 2a is the thickness of the initial velocity shear layer and V0 is the total jump of the flow velocity across the magnetospheric boundary, and it increases with MA , and for MA > 5.0 it is equal to ∼0.2 × 2aV0 . For a reasonable set of parameters at the dayside magnetospheric boundary the anomalous viscosity obtained is just the right magnitude for driving a magnetospheric convection in the terrestrial magnetosphere. | |||||
| 書誌情報 |
Journal of geophysical research. A 巻 92, 号 4, p. 3195-3206, 発行日 1987-04 |
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| ISSN | ||||||
| 収録物識別子タイプ | ISSN | |||||
| 収録物識別子 | 01480227 | |||||
| 書誌レコードID | ||||||
| 収録物識別子タイプ | NCID | |||||
| 収録物識別子 | AA10819721 | |||||
| DOI | ||||||
| 識別子タイプ | DOI | |||||
| 関連識別子 | info:doi/10.1029/JA092iA04p03195 | |||||
| 権利 | ||||||
| 権利情報 | copyright 1987 by the American Geophysical Union | |||||
| 日本十進分類法 | ||||||
| 主題Scheme | NDC | |||||
| 主題 | 450 | |||||
| 出版者 | ||||||
| 出版者 | American Geophysical Union | |||||
