THEMIS observation of multiple dipolarization fronts and associated wave characteristics in the near‐Earth magnetotail
THEMIS observation of multiple dipolarization fronts and associated wave characteristics in the near‐Earth magnetotail
复制标题
DOI：
10.1029/2009gl040663
复制
发表时间：
2009-10
影响因子：
5.2
通讯作者：
Meng Zhou;M. Ashour‐Abdalla;Xiaohua Deng;D. Schriver;M. El‐Alaoui;Y. Pang
中科院分区：
文献类型：
--
作者：
Meng Zhou;M. Ashour‐Abdalla;Xiaohua Deng;D. Schriver;M. El‐Alaoui;Y. Pang
在亚暴期间，THEMIS航天器在近地磁尾观测到多个偶极锋。偶极锋位于向地传播的等离子体泡的前缘。主要的高能电子通量的增强，观察到在双极化前沿，这也与大波波动从下面的较低的混合频率以上的电子回旋频率延伸。强电场波包，主要由霍尔电场和低杂波漂移（LHD）波，被观察到的权利，在前面，这是一个薄的电流层的离子惯性长度的顺序的大小。LHD波被认为是由存在密度和温度梯度的反磁电流产生的。静电电子回旋谐波（ECH）波被检测到稍后的前端。ECH波可能是由电子垂直速度分布的正斜率产生的。这两种波都被认为能够加热电子。这些波在偶极前沿的观察可能是重要的亚暴注入过程中的电子振荡的理解，以及电流中断的机制。
Multiple dipolarization fronts were observed by THEMIS spacecraft in the near‐Earth magnetotail during a substorm. The dipolarization fronts were located at the leading edge of earthward propagating plasma bubbles. Major energetic electron flux enhancements were observed at the dipolarization fronts, which were also associated with large wave fluctuations extending from below the lower hybrid frequency to above the electron cyclotron frequency. Intense electric field wave packets, primarily contributed by the Hall electric field and lower hybrid drift (LHD) wave, were observed right at the front, which was a thin current layer with size of the order of the ion inertial length. The LHD wave was believed to be generated by a diamagnetic current in the presence of density and temperature gradients. Electrostatic electron cyclotron harmonic (ECH) waves were detected slightly after the front. The ECH waves were probably generated by the positive slope of the electron perpendicular velocity distribution. Both of these waves are suggested to be able to heat electrons. The observation of these waves at the dipolarization front could be important for the understanding of electron energization during substorm injection, as well as the mechanism of current disruption.