Based on particle-in-cell (PIC) simulation results of collisionless driven reconnection in a steady state, an effective resistivity model is developed for a magnetohydrodynamic (MHD) simulation in order to bridge the huge gap between macro- and microphysics of magnetic reconnection. The PIC simulation reveals that the reconnection electric field sustained by microscopic physics is found to evolve so as to balance the flux inflow rate, which is determined by global dynamics in a macroscopic system. This effective resistivity model is applied to MHD phenomena controlled by magnetic reconnection in the Earth's magnetosphere. Although this model does not include any adjustable parameters related to kinetic dissipation processes, some global phenomena such as the onset of magnetic substorm, dipolarization and propagation of flux rope, detailed processes of which are longstanding questions, are reproduced well in the MHD simulation and are consistent with the observations.
基于无碰撞重联在稳态下的粒子网格（PIC）模拟结果，为磁流体动力学（MHD）模拟开发了一种有效电阻率模型，以弥合磁重联宏观与微观物理之间的巨大鸿沟。PIC模拟揭示，由微观物理维持的重联电场会演化以平衡磁通量流入速率，而该速率由宏观系统中的全局动力学决定。该有效电阻率模型被应用于地球磁层中由磁重联控制的MHD现象。尽管该模型不包含与动力学耗散过程相关的可调参数，但一些全局现象，如磁层亚暴的触发、偶极化以及磁通量绳的传播——其详细过程长期以来一直是未解之谜——在MHD模拟中得到了很好的再现，并与观测结果一致。