Cluster observations of hot flow anomalies with large flow deflections: 2. Bow shock geometry at HFA edges
Cluster observations of hot flow anomalies with large flow deflections: 2. Bow shock geometry at HFA edges
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具有大流动偏转的热流异常的集群观测：2. HFA 边缘的弓形激波几何形状
DOI：
10.1029/2012ja018204
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发表时间：
2013-01
影响因子：
--
通讯作者：
S Wang, Q Zong
中科院分区：
文献类型：
--
作者：
S Wang, Q Zong
基于2003 - 2009年C1卫星观测到的87个热流异常区，对热流异常区边缘的弓形激波几何结构进行了实例和统计研究。结果表明，HFA可以形成在准平行和准垂直冲击。在随附的论文中，我们表明离子可能在弓形激波处被近镜面反射，并与太阳风相互作用形成HFA。镜面反射离子的引导中心通常将在准垂直冲击下向下游扫到弓形冲击。然而，这项研究表明，在这87个高频附件中，至少有13个（15%）的前缘和后缘都处于准垂直激波。这些HFA显示出高的回转速度和高的快磁音速马赫数，增加了陀螺半径和俯仰角散射的可能性，这可能有助于离子从弓形激波中逃逸并向上游移动。此外，在准垂直冲击下，具有两个边缘的HFAs比在准平行冲击下具有两个边缘的HFAs更接近弓形冲击。这可能有助于反射离子在准垂直冲击后立即与入射太阳风相互作用，并增加HFA形成的可能性。
Case and statistical studies of the bow shock geometry at hot flow anomaly (HFA) edges have been performed based on 87 HFAs with large flow deflections observed by the Cluster C1 spacecraft from 2003 to 2009. The results suggest that HFAs can be formed at both quasi‐parallel and quasi‐perpendicular shocks. In an accompanying paper, we show that the ions might be near‐specularly reflected at the bow shock and interact with the solar wind to form HFAs. The guiding center of specularly reflected ions will typically be swept downstream to the bow shock at quasi‐perpendicular shocks. However, this study shows that in at least 13 of these 87 (15%) HFAs, both the leading and trailing edges are at quasi‐perpendicular shocks. These HFAs show a high gyration velocity and a high fast magneto‐sonic Mach number, increasing the gyro‐radius and the possibility of pitch angle scattering, which might help the ions escape from the bow shock and move upstream. In addition, HFAs with both edges at quasi‐perpendicular shocks are closer to the bow shock than those with both edges at quasi‐parallel shocks. This might help the reflected ions at a quasi‐perpendicular shock interact with the incident solar wind immediately after the reflection and increase the possibility of HFA formation.
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通讯作者：
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影响因子：
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