In‐Situ Observation of Magnetic Null on 19 September 2015 Event Using Magnetospheric Multiscale Mission
In‐Situ Observation of Magnetic Null on 19 September 2015 Event Using Magnetospheric Multiscale Mission
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DOI：
10.1029/2021ja029571
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发表时间：
2023-01
期刊：
影响因子：
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通讯作者：
S. Ekawati;D. Cai
中科院分区：
文献类型：
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作者：
S. Ekawati;D. Cai
在本文中，我们使用线性插值来检测MMS航天器（SC）四面体内部的磁零点，这对于像MMS这样的非常小的SC间分离几乎是不可能的（以前在集群使命上实现，这是更大的分离SC）。我们还报告说，连续或相同的磁零进入/重新进入并穿过MMS航天器四面体，并且在2015年9月19日事件期间，当它穿过四个MMS四面体表面之一时，磁零的“分叉”（零类型的变化）被捕获。在此事件期间，我们观察到进入并穿过MMS四面体的径向零值的本征值从所有真实的变化到一个共轭复对和一个真实的本征值，当零值通过四面体边界单元之一时。这种分叉也可以通过使用地球移动器距离测量“分叉”前后两个零值之间的拓扑距离来证明。
In this paper, we detect a magnetic null inside the MMS space‐craft (SC) tetrahedron using a linear interpolation that might be nearly impossible for very small inter‐SC separation like MMS (previously implemented on Cluster mission which is larger separation SC). We also report, successive or identical magnetic nulls that enter/reenter and cross the MMS spacecraft tetrahedron, and the “bifurcations” (change of the null type) of magnetic nulls are captured when it crosses one of four MMS tetrahedral surfaces during the 19 September 2015 event. During this event, we observe the eigenvalues of the radial null that enters and crosses the MMS tetrahedron changes from all real to one conjugate complex pair and one real eigenvalues, when the null exits through one of the tetrahedral boundary cells. This bifurcation is also evidenced by measuring the topological distance between two nulls before and after “bifurcation” using the Earth Mover's Distance.