Lower hybrid drift instability at a dipolarization front
Lower hybrid drift instability at a dipolarization front
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DOI：
10.1002/2014ja020528
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发表时间：
2015-02
期刊：
影响因子：
--
通讯作者：
A. Divin;Y. Khotyaintsev;A. Vaivads;M. André
中科院分区：
文献类型：
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作者：
A. Divin;Y. Khotyaintsev;A. Vaivads;M. André
我们提出了由星系团卫星在地球磁尾探测到的重联射流锋的观测结果，这通常被称为双极化锋。我们详细研究了在锋面观测到的频率在较低混合范围内，振幅达到40 mV/m的电场结构。我们确定了这些结构在锋面参考系中的频率和相速度，并将它们识别为锋面急剧密度梯度激发的低混合漂移不稳定性（LHDI）的表现。当结构的静电势相当于电子温度的~ 10%时，观察到LHDI处于其演化的非线性阶段。锋面在离子和MHD尺度上表现为一个连贯的结构，表明在LHDI的激发和锋面陡峭密度梯度的恢复之间存在一个动态平衡。
We present observations of a reconnection jet front detected by the Cluster satellites in the magnetotail of Earth, which are commonly referred to as dipolarization fronts. We investigate in detail electric field structures observed at the front which have frequency in the lower hybrid range and amplitudes reaching 40 mV/m. We determine the frequency and phase velocity of these structures in the reference frame of the front and identify them as a manifestation of the lower hybrid drift instability (LHDI) excited at the sharp density gradient at the front. The LHDI is observed in the nonlinear stage of its evolution as the electrostatic potential of the structures is comparable to ∼ 10% of the electron temperature. The front appears to be a coherent structure on ion and MHD scales, suggesting existence of a dynamic equilibrium between excitation of the LHDI and recovery of the steep density gradient at the front.