论文标题

无碰撞磁重新连接中非甲状腺电子压力效应的数值研究

Numerical study of non-gyrotropic electron pressure effects in collisionless magnetic reconnection

论文作者

Sladkov, A., Smets, R., Aunai, N., Korzhimanov, A.

论文摘要

我们研究了在最初受扰动的哈里斯纸中研究二维重新连接过程的杂种代码研究后果中六组分电子压力张量的时间演变。我们提出,除非考虑各向同性化算子,否则两个张量成分(一个对角线和一个非对角线)以不稳定的方式生长。该各性化项在物理上与电子热通量相关。结果,我们提出,在次离子尺度的场逆转中,观察到对角线成分的增强值。由于动力学压力的增加,该电子层中的磁场降低,因此增加了边缘的平面外电流并导致其分叉。分叉机制基于电子压力各向异性的存在,与流入电子大体速度的梯度有关。在增强的对角线压力张量成分的流入方向上的梯度导致进入X点区域的离子减速。我们建议,由六组分电子压力张量的各向异性/天性产生的分叉电流表对应于与非构造的较小的重新连接速率相对应的较小的重新连接速率。

We investigate the time evolution of the six-component electron pressure tensor in a hybrid code studying consequences for the two-dimensional reconnection process in an initially perturbed Harris sheet. We put forward that two tensor components (a diagonal and a non-diagonal one) grow in an unstable way unless an isotropization operator is considered. This isotropization term is physically associated with an electron heat flux. As a consequence, we put forward that an enhanced value of a diagonal component is observed in the very middle of field reversal at sub-ion scale. Because of the increase of the kinetic pressure, the magnetic field is decreased in this electron layer, hence increasing the associated out-of-plane current at its edges and leading to its bifurcation. The bifurcation mechanism is based on the presence of electron pressure anisotropy, related to the gradient of inflow electron bulk velocity. The gradient in the inflow direction of the enhanced diagonal electron pressure tensor component results in the deceleration of the ions entering the X-point region. We suggest that bifurcated current sheets resulting from the anisotropies/agyrotropies of the six-component electron pressure tensor correspond to smaller reconnection rates comparing to non-bifurcated ones.

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