论文标题
无碰撞磁重新连接的磁流失动力学模拟的有效电阻率
Effective resistivity for magnetohydrodynamic simulation of collisionless magnetic reconnection
论文作者
论文摘要
电子惯性期限和非对角性电子压力项在无碰撞磁重新连接中的冷冻状态分解中众所周知，它们自然具有动力学且难以在磁性水力动力学（MHD）模拟中使用。在考虑了MHD和Hall MHD的缺点之后，研究了扩散区域中电子和离子的动力学特性，并研究了涉及带电颗粒的动力学的有效电阻率模型[Z。 W. Ma等。 2018 Sci。众议员8 10521]。有效电阻率的幅度主要由在具有较大的离子电子质量比的最现实情况下电子确定。在这项工作中，在2.5D MHD和Hall MHD模拟中成功应用了无碰撞磁重新连接的有效电阻率模型，与传统的MHD模型相比，该模型可显着改善模拟结果。对于MHD情况，有效电阻率将重新连接率显着提高到〜0.1 $ B_0V_A $的合理值。对于具有有效电阻率的HALL MHD情况，峰重新连接速率为〜0.25 $ B_0V_A $，重新连接场的主要结构和当前纸张与粒子中的粒子（PIC）和混合模拟都很好地吻合。
The electron inertia term and the off-diagonal electron pressure terms are well-known for the frozen-in condition breakdown in collisionless magnetic reconnection, which are naturally kinetic and difficult to be employed in magnetohydrodynamic (MHD) simulations. After considering the shortcomings of MHD and Hall MHD in neglecting the important electron dynamics such as the inertia and the nongyrotropic pressure, the kinetic characteristics of electrons and ions in the diffusion region are studied and an effective resistivity model involving dynamics of charged particles is proposed [Z. W. Ma et al. 2018 Sci. Rep. 8 10521]. The amplitude of the effective resistivity is mainly determined by electrons in most realistic situations with large ion-electron mass ratios. In this work, the effective resistivity model for collisionless magnetic reconnection without the guide field is successfully applied in the 2.5D MHD and Hall MHD simulations, which remarkably improves the simulation results compared with traditional MHD models. For the MHD case, the effective resistivity significantly increased the reconnection rate to the reasonable value of ~0.1$B_0v_A$. For the Hall MHD case with effective resistivity, the peak reconnection rate is ~0.25$B_0v_A$, and the major structures of the reconnecting field and the current sheet agree well with the particle-in-cell (PIC) and hybrid simulations.
