Shock waves standing in the middle‐ and high‐latitude magnetosheath from global MHD simulations
Shock waves standing in the middle‐ and high‐latitude magnetosheath from global MHD simulations
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DOI：
10.1029/2010ja016268
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发表时间：
2011-03
影响因子：
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通讯作者：
Xuelian Guo;Chunmiao Wang;T. Sun;Y. Hu
中科院分区：
文献类型：
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作者：
Xuelian Guo;Chunmiao Wang;T. Sun;Y. Hu
通过全球磁流体动力学模拟，发现中高纬度磁鞘中存在驻激波（SSW）。恒定北向（或南向）行星际磁场（IMF）有两个（或一个）SSW；它们延伸到磁鞘区域并进一步与弓激波相互作用。由于SSW向行星际空间延伸，特别是当IMF转向南时，磁层前面会出现锯齿状的弓形激波。 SSW 是由磁鞘中超磁音速太阳风流中磁层顶的凹痕激发的；对于北向IMF，其中一个凹痕位于尖点区域，另一个对应于尖点尾部的中性点；对于南向 IMF，凹口仅位于尖点区域。我们检查了激波锋面的朗肯-于贡尼奥关系，发现数值模型结果与理论预测一致。
Standing shock waves (SSWs) are found to exist in the middle-and high-latitude magnetosheath through the global magnetohydrodynamic simulations. There are two (or one) SSWs for constant northward (or southward) interplanetary magnetic field (IMF); they extend into the magnetosheath region and further interact with the bow shock. Because of the extension of SSWs into the interplanetary space, especially when IMF turns southward, an indented bow shock emerges in front of the magnetosphere. The SSWs are excited by the indentations of the magnetopause in the supermagnetosonic solar wind flows in the magnetosheath; for northward IMF, one of the indentations is located in the cusp region and the other corresponds to the neutral point in the tailward of the cusp; for southward IMF, the indentation simply locates in the cusp region. We examine the Rankine-Hugoniot relations across the shock fronts and find the numerical model results are consistent with theoretical predictions.