Understanding the dynamic evolution of relativistic electrons in the Earth's radiation belts during both storm and nonstorm times is a challenging task. The U.S. National Science Foundation's Geospace Environment Modeling (GEM) focus group “Quantitative Assessment of Radiation Belt Modeling” has selected two storm time and two nonstorm time events that occurred during the second year of the Van Allen Probes mission for in‐depth study. Here, we perform simulations for these GEM challenge events using the 3D Versatile Electron Radiation Belt code. We set up the outer L^* boundary using data from the Geostationary Operational Environmental Satellites and validate the simulation results against satellite observations from both the Geostationary Operational Environmental Satellites and Van Allen Probe missions for 0.9‐MeV electrons. Our results show that the position of the plasmapause plays a significant role in the dynamic evolution of relativistic electrons. The magnetopause shadowing effect is included by using last closed drift shell, and it is shown to significantly contribute to the dropouts of relativistic electrons at high L^*. We perform simulations using four different empirical radial diffusion coefficient models for the GEM challenge events, and the results show that these simulations reproduce the general dynamic evolution of relativistic radiation belt electrons. However, in the events shown here, simulations using the radial diffusion coefficients from Brautigam and Albert (2000) produce the best agreement with satellite observations.

中文翻译：

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等离子体边界对相对论辐射带电子动态演化的影响

了解风暴和非风暴期间地球辐射带中相对论电子的动态演化是一项艰巨的任务。美国国家科学基金会的地理空间环境建模（GEM）焦点小组“辐射带建模的定量评估”选择了Van Allen Probes任务第二年发生的两个风暴时间和两个非风暴时间事件进行深入研究。在这里，我们使用3D通用电子辐射带代码对这些GEM挑战事件进行仿真。我们设置外部L ^*使用对地静止环境卫星的数据进行边界分析，并根据对地静止环境卫星和Van Allen Probe任务对0.9MeV电子的卫星观测结果验证仿真结果。我们的结果表明，等离子体暂停的位置在相对论电子的动态演化中起着重要作用。最后一个封闭的漂移壳包括了磁层顶的遮蔽效应，并且显示出它对高L ^*时相对论电子的丢失有显着贡献^。。我们对GEM挑战事件使用四个不同的经验径向扩散系数模型执行模拟，结果表明这些模拟重现了相对论辐射带电子的一般动态演化。但是，在这里显示的事件中，使用来自Brautigam和Albert的径向扩散系数（2000）进行的模拟与卫星观测产生了最好的一致性。