We report a two-step dropout event of radiation belt electron phase space density (PSD) induced by a typical magnetic cloud (MC) that drove an intense geomagnetic storm. The first and second steps of PSD dropout occurred, respectively, in the initial and main phases of the storm with a short-time partial recovery between the two dropouts. In this event, the initial phase after the sudden commencement lasted for near 21 hr, which gives an ideal opportunity to investigate the nature of the radiation belt electron dropout by isolating the main phase from any losses occurring during the initial phase. Detailed analysis shows that the first step of the dropout in the initial phase is likely associated with the magnetopause shadowing effect in combination with ultra-low frequency wave-induced outward transport caused by sustaining enhanced dynamic pressure activity before the MC. Comparably, the prolonged strong southward interplanetary magnetic field inside the MC that resulted in th...

中文翻译：

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磁云事件引起的辐射带电子相空间密度的两步下降

我们报告了由典型的磁云（MC）引发的强烈地磁风暴引起的辐射带电子相空间密度（PSD）的两步下降事件。PSD丢失的第一步和第二步分别发生在风暴的初始阶段和主要阶段，两次丢失之间有短时间的部分恢复。在这种情况下，突然开始后的初始阶段持续了将近21小时，这为通过将主相与初始阶段发生的任何损失隔离开来，研究辐射带电子漏失的性质提供了理想的机会。详细的分析表明，初始阶段的辍学的第一步可能与绝经期的阴影效应有关，再加上MC之前维持增强的动态压力活动所引起的超低频波诱导的向外传输。相比之下，MC内部长时间的强南向行星际磁场导致了...