A Framework for Understanding and Quantifying the Loss and Acceleration of Relativistic Electrons in the Outer Radiation Belt During Geomagnetic Storms

We present detailed analysis of the global relativistic electron dynamics as measured by total radiation belt content (RBC) during coronal mass ejection (CME) and corotating interaction region (CIR)‐driven geomagnetic storms. Recent work has demonstrated that the response of the outer radiation belt is consistent and repeatable during geomagnetic storms. Here we build on this work to show that radiation belt dynamics can be divided into two sequential phases, which have different solar wind dependencies and which when analyzed separately reveal that the radiation belt responds more predictably than if the overall storm response is analyzed as a whole. In terms of RBC, in every storm we analyzed, a phase dominated by loss is followed by a phase dominated by acceleration. Analysis of the RBC during each of these phases demonstrates that they both respond coherently to solar wind and magnetospheric driving. However, the response is independent of whether the storm response is associated with either a CME or CIR. Our analysis shows that during the initial phase, radiation belt loss is organized by the location of the magnetopause and the strength of Dst and ultralow frequency wave power. During the second phase, radiation belt enhancements are well organized by the amplitude of ultralow frequency waves, the auroral electroject index, and solar wind energy input. Overall, our results demonstrate that storm time dynamics of the RBC is repeatable and well characterized by solar wind and geomagnetic driving, albeit with different dependencies during the two phases of a storm.

我们对在日冕物质抛射（CME）和共转相互作用区（CIR）驱动的地磁暴期间通过辐射带总含量（RBC）测量的全球相对论电子动力学进行了详细分析。近期的研究表明，在外层辐射带在地磁暴期间的响应是一致且可重复的。在此基础上，我们的研究表明辐射带动力学可分为两个连续的阶段，这两个阶段对太阳风有不同的依赖关系，并且当分别进行分析时发现，与将整个暴的响应作为一个整体进行分析相比，辐射带的响应更具可预测性。就辐射带总含量而言，在我们分析的每一次磁暴中，一个以损失为主的阶段之后是一个以加速为主的阶段。对每个阶段的辐射带总含量的分析表明，它们都对太阳风和磁层驱动有一致的响应。然而，这种响应与磁暴响应是与日冕物质抛射还是共转相互作用区相关无关。我们的分析表明，在初始阶段，辐射带的损失由磁层顶的位置、Dst的强度以及超低频波功率所决定。在第二阶段，辐射带的增强由超低频波的振幅、极光电集流指数以及太阳风能输入很好地决定。总体而言，我们的结果表明，辐射带总含量的暴时动力学是可重复的，并且由太阳风和地磁驱动很好地表征，尽管在磁暴的两个阶段有不同的依赖关系。