High‐Resolution Measurements of the Cross‐Shock Potential, Ion Reflection, and Electron Heating at an Interplanetary Shock by MMS
High‐Resolution Measurements of the Cross‐Shock Potential, Ion Reflection, and Electron Heating at an Interplanetary Shock by MMS
复制标题
利用 MMS 对行星际激波中的交叉激波势、离子反射和电子加热进行高分辨率测量
DOI：
10.1029/2018ja026197
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发表时间：
2019
期刊：
影响因子：
--
通讯作者：
J. Burch
中科院分区：
文献类型：
--
作者：
I. Cohen;S. Schwartz;K. Goodrich;N. Ahmadi;R. Ergun;S. Fuselier;M. Desai;E. Christian;D. McComas;G. Zank;J. Shuster;S. Vines;B. Mauk;R. Decker;B. Anderson;J. Westlake;O. Contel;H. Breuillard;B. Giles;R. Torbert;J. Burch
磁层多尺度(MMS)航天器在2018年1月8日获得了前所未有的高时间分辨率多点粒子和行星际激波事件的场测量。航天器在接近25RE的远地点时，在弓形激波上游的原始太阳风中遇到了正向/反向激波对的超临界正向激波。这四个航天器的高时间分辨率测量仅相隔约20公里，可以直接测量粒子分布，揭示了电子加热和近镜面反射离子的证据。交叉激波电势直接由三维电场测量得到。这是第一次在近镜面反射离子的行星际激波中直接观测到高时间分辨率(<；1 S)。交叉激波势的计算产生了一个足以反映至少部分来自入射太阳风束的质子的势跳跃。这里计算的交叉激波势与以前基于粒子测量和数值/分析模拟的估计是一致的。从电子压张量的四个航天器发散计算出的双极对交叉激波势的贡献略高于从激波中的Liouville映射的电子能量增益所推断的贡献。此外，本文报道的高时间分辨率三维电场测量揭示了嵌入激波层的小尺度非线性结构对非单调激波相变的贡献。
The Magnetospheric Multiscale (MMS) spacecraft obtained unprecedented high‐time resolution multipoint particle and field measurements of an interplanetary shock event on 8 January 2018. The spacecraft encountered the supercritical forward shock of a forward/reverse shock pair in the pristine solar wind upstream of the bow shock near the subsolar point as they neared apogee at ~25 RE. The high‐time resolution measurements from the four spacecraft, separated by only ~20 km, allowed direct measurement of particle distributions revealing evidence of electron heating and near specularly reflected ions. The cross‐shock potential is calculated directly from 3‐D electric field measurements. This is the first reported direct high temporal resolution (<1 s) observation at an interplanetary shock of near specularly reflected ions. Calculation of the cross‐shock potential yields a potential jump significant enough to reflect at least some of the protons from the incident solar wind beam. The cross‐shock potential calculated here is consistent with previous estimations based on particle measurements and numerical/analytical simulations. The ambipolar contribution to the cross‐shock potential calculated from the four‐spacecraft divergence of the electron pressure tensor is somewhat higher than that inferred form the Liouville‐mapped electron energy gain across the shock. Furthermore, the high‐time‐resolution 3‐D electric field measurements reported here reveal small‐scale nonlinear structures embedded in the shock layer that contribute to the nonmonotonic shock transition.
使用聚类数据估计交叉冲击电势的三种方法的比较
影响因子：
1.9
作者：
Dimmock A
通讯作者：
Dimmock A