Turbulence and Transport During Guide Field Reconnection at the Magnetopause
Turbulence and Transport During Guide Field Reconnection at the Magnetopause
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DOI：
10.1029/2019ja027498
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发表时间：
2020-04-01
影响因子：
2.8
通讯作者：
Graham, D. B.
中科院分区：
文献类型：
--
作者：
Price, L.;Swisdak, M.;Graham, D. B.
基于磁层多尺度(MMS)任务的观测数据，分析了磁层顶磁场磁场重联的三维粒子模拟中湍流的发展和影响。沿着分离线，湍流是低混合漂移不稳定(LHDI)的变体，它产生的电场波动的幅度远远大于重联电场。尽管电子仍然冻结在磁场中，但湍流控制着密度和电流分布的标尺长度，同时使磁层顶上的大量传输得以实现。面外电流密度的输运超过粒子密度的输运。在X线附近，电子没有被冻结，而不同于LHDI的湍流通过反常粘性对广义欧姆定律做出了显著的净贡献。湍流和相关粒子输运的特征与MMS观测中的涨落幅度是一致的。然而，对于这一事件，模拟表明，MMS航天器距离电子扩散区域的核心不够近，无法确定异常粘性很重要的区域。
We analyze the development and influence of turbulence in three-dimensional particle-in-cell simulations of guide field magnetic reconnection at the magnetopause with parameters based on observations from the Magnetospheric Multiscale (MMS) mission. Along the separatrices the turbulence is a variant of the lower-hybrid-drift instability (LHDI) that produces electric field fluctuations with amplitudes much greater than the reconnection electric field. The turbulence controls the scale length of the density and current profiles while enabling significant transport across the magnetopause, despite the electrons remaining frozen-in to the magnetic field. Transport of the out-of-plane current density exceeds that of the particle density. Near the X-line the electrons are not frozen-in and the turbulence, which differs from the LHDI, makes a significant net contribution to the generalized Ohm's law through an anomalous viscosity. The characteristics of the turbulence and associated particle transport are consistent with fluctuation amplitudes in the MMS observations. However, for this event the simulations suggest that the MMS spacecraft were not close enough to the core of the electron diffusion region to identify the region where anomalous viscosity is important.