The magnetosphere under the radial interplanetary magnetic field: A numerical study

作者：B. B. Tang(bbtang@spaceweather.ac.cn), C. Wang, and W. Y. Li

摘要：

We investigate the magnetosphere under radial interplanetary magnetic fields (IMF)

by using global magnetohydrodynamic simulations. The magnetosphere-ionosphere

system falls into an unexpected state under this specific IMF orientation when the solar

wind electric field vanishes. The most important features that characterize this state

include (1) magnetic reconnections can still occur, which take place at the equatorward of

the cusp in one hemisphere, the tailward of the cusp in the other hemisphere, and also in

the plasma sheet; (2) significant north-south asymmetry exists in both magnetosphere and

ionosphere; (3) the polar ionosphere mainly presents a weak two-cell convection pattern,

with the polar cap potential valued at 30 kV; (4) the whole magnetosphere-ionosphere

system stays in a very quiet state, and the AL index does not exceed –70 nT; and (5) the

Kelvin-Helmholtz instability can still be excited at both flanks of the magnetosphere.

These results imply the controlling role of the IMF direction between the solar wind and

magnetosphere interactions and improve our understanding of the solar

wind-magnetosphere-ionosphere system.

自评：径向IMF下太阳风电场消失，这时磁层重联还会发生吗？本文从全球模拟出发进行了讨论，并给出了之后磁层活动一些有趣的地方。这些论述希望能在之后获得更多的支撑验证。

具体请参见：http://onlinelibrary.wiley.com/doi/10.1002/2013JA019155/full

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