A three-dimensional MHD simulation of the interaction of the solar wind with the earth's magnetosphere - The generation of field-aligned currents
A three-dimensional MHD simulation of the interaction of the solar wind with the earth's magnetosphere - The generation of field-aligned currents
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DOI：
10.1029/ja091ia06p06791
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发表时间：
1986-06
影响因子：
--
通讯作者：
T. Ogino
中科院分区：
文献类型：
--
作者：
T. Ogino
利用三维磁流体动力学模型对太阳风与地球磁层的相互作用进行了全球计算机模拟。因此，我们能够重现准稳态磁层配置和Birkeland场对齐的电流系统，这取决于行星际磁场（IMF）的z分量的极性。双对流单体和黎明到黄昏的电位为30-100千伏出现在赤道的磁层。观察到四种类型的场向电流。在所有IMF条件下产生的区域1和2场向电流分别为0.6-1.0×106 A和0.15-0.61×106 A。在高纬度地区的区域1电流产生的磁场对齐涡的侧翼通过粘性相互作用，并加强了扭曲的开放磁场线在尾部区域向南IMF。另一方面，低纬2区电流可能主要是由等离子体片的内压梯度产生的。从模拟中获得的区域1电流与我们的本地化阿尔芬模式的理论分析的估计值吻合得很好。另外两种类型的场向电流是向阳侧磁层顶电流的向阳侧尖点区域，这增加了北IMF，和向阳侧尖点电流南IMF。尖电流与磁层顶区的开放磁力线的扭曲有关。
A global computer simulation of the interaction of the solar wind with the earth's magnetosphere was executed by using a three-dimensional magnetohydrodynamic model. As a result, we were able to reproduce quasi-steady-state magnetospheric configurations and a Birkeland field-aligned current system which depend on the polarity of the z component of the interplanetary magnetic field (IMF). Twin convection cells and a dawn to dusk electric potential of 30–100 kV appeared at the equator in the magnetosphere. Four types of field-aligned currents were observed. Region 1 and 2 field-aligned currents generated for all IMF conditions were 0.6–1.0×106 A and 0.15–0.61×106 A, respectively, in the total current. Region 1 currents at high latitudes are generated from the field-aligned vorticity at the flanks through a viscous interaction and are strengthened by a twisting of open magnetic field lines in the tail region for southward IMF. On the other hand, the low-latitude region 2 currents probably are generated mainly from the inner pressure gradient of the plasma sheet. The region 1 current obtained from the simulation was in good agreement with an estimate from our theoretical analysis of the localized Alfven mode. The other two types of field-aligned currents are the dayside magnetopause currents in the dayside cusp region, which increase for northward IMF, and the dayside cusp currents for southward IMF. The cusp currents are associated with a twisting of open magnetic field lines in the magnetopause region.