Double Layers in the Earth's Bow Shock
Double Layers in the Earth's Bow Shock
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DOI：
10.1029/2022gl101348
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发表时间：
2022-11
影响因子：
5.2
通讯作者：
Jie Sun;I. Vasko;S. Bale;Rachel Wang;F. Mozer
中科院分区：
文献类型：
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作者：
Jie Sun;I. Vasko;S. Bale;Rachel Wang;F. Mozer
我们提出了磁层多尺度观测的静电双层准垂直地球的弓形冲击。这些双层主要具有幅度高达100 mV/m的平行电场，空间宽度为50-700 m，等离子体帧速度在100 km/s以内。在德霍夫曼-泰勒坐标系中，跨单个双层的电势降是交叉激波电势的2%-7%，并且发生在10德拜长度或电子惯性长度的十分之一的空间尺度上。一些双层可以具有70德拜长度的空间宽度和高达交叉冲击电位的30%的电位降。在双层中观察到的电子温度变化与它们的电位降大致一致。虽然地球弓形激波中的电子加热主要是由于de Hoffmann-Teller框架中的准静态电场，但这些观察表明电子温度也可以在德拜尺度静电结构中增加。
We present Magnetospheric Multiscale observations of electrostatic double layers in quasi‐perpendicular Earth's bow shock. These double layers have predominantly parallel electric field with amplitudes up to 100 mV/m, spatial widths of 50–700 m, and plasma frame speeds within 100 km/s. The potential drop across a single double layer is 2%–7% of the cross‐shock potential in the de Hoffmann‐Teller frame and occurs over the spatial scale of 10 Debye lengths or one tenth of electron inertial length. Some double layers can have spatial width of 70 Debye lengths and potential drop up to 30% of the cross‐shock potential. The electron temperature variation observed across double layers is roughly consistent with their potential drop. While electron heating in the Earth's bow shock occurs predominantly due to the quasi‐static electric field in the de Hoffmann‐Teller frame, these observations show that electron temperature can also increase across Debye‐scale electrostatic structures.