We use the magnetohydrodynamic (MHD) with embedded particle‐in‐cell model (MHD‐EPIC) to study the Geospace Environment Modeling (GEM) dayside kinetic processes challenge event at 01:50–03:00 UT on 18 November 2015, when the magnetosphere was driven by a steady southward interplanetary magnetic field (IMF). In the MHD‐EPIC simulation, the dayside magnetopause is covered by a PIC code so that the dayside reconnection is properly handled. We compare the magnetic fields and the plasma profiles of the magnetopause crossing with the MMS3 spacecraft observations. Most variables match the observations well in the magnetosphere, in the magnetosheath, and also during the current sheet crossing. The MHD‐EPIC simulation produces flux ropes, and we demonstrate that some magnetic field and plasma features observed by the MMS3 spacecraft can be reproduced by a flux rope crossing event. We use an algorithm to automatically identify the reconnection sites from the simulation results. It turns out that there are usually multiple X‐lines at the magnetopause. By tracing the locations of the X‐lines, we find that the typical moving speed of the X‐line endpoints is about 70 km/s, which is higher than but still comparable with the ground‐based observations.

中文翻译：

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磁流体动力学与嵌入式粒子在地空间环境中模拟白天动力学过程挑战事件的模拟

我们将磁流体动力学（MHD）与嵌入式粒子模型（MHD-EPIC）结合使用，研究了2015年11月18日UT 01：50–03：00 UT的地理空间环境建模（GEM）白天动力学过程挑战事件。磁层由稳定的向南行星际磁场（IMF）驱动。在MHD-EPIC模拟中，白天的磁更年期被PIC代码覆盖，以便正确处理白天的重新连接。我们与MMS3航天器的观测结果比较了更年期的磁场和等离子体剖面。大多数变量与磁层，磁石荒地以及当前工作表穿越过程中的观测结果非常匹配。MHD-EPIC仿真产生助焊剂绳，并且我们证明了MMS3航天器观测到的某些磁场和等离子体特征可以通过通量绳穿越事件来再现。我们使用一种算法从仿真结果中自动识别重新连接站点。事实证明，磁更年期通常有多条X线。通过追踪X线的位置，我们发现X线端点的典型移动速度约为70 km / s，虽然高于但仍可与地面观测相媲美。