发表机构
Nanjing University; University of Turku（南京大学; 图尔库大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
该研究结合多源观测与模拟，发现大规模行星际结构（如CME、SIR、ICME）可优化上游磁环境，显著增强行星际激波对电子的加速效率，揭示了高能电子增强的关键机制。
AI 中文摘要
包括先前日冕物质抛射（CME）和流相互作用区（SIR）在内的大规模预先存在的行星际结构，在塑造高能电子的激波加速环境中的作用尚未完全明确。本研究调查了太阳与日球层观测台（STEREO）观测到的9个与显著MeV电子增强相关的行星际激波，因为此类增强在行星际激波中很少被观测到。我们结合遥感观测、基于拖曳的建模和原位测量，分析激波在预先存在的行星际结构中的传播情况。9个事件中有8个与先前的慢速或中等速度CME相关，而6个激波被原位观测到在先前的ICME（日冕物质抛射）内传播，表明大规模上游捕获结构是这些事件的共同特征。进一步分析确定了与电子加速增强相关的三种不同情景：激波在先前ICME中传播、激波-SIR相互作用，以及耀斑加速电子直接注入SIR。作为典型的ICME内激波事件，我们结合观测和一维蒙特卡洛测试粒子模拟，对2012年1月29日的低β准垂直激波（θBn≈87°）进行了进一步研究，该激波传播至大规模上游磁环中。模拟显示，上游磁环延长了电子在激波附近的停留时间，并大幅提高了加速效率。这些结果表明，大规模行星际结构可预先调整上游磁环境，为电子的长时间停留和高效激波加速提供有利条件。
英文摘要
The role of large-scale pre-existing interplanetary structures, including preceding coronal mass ejections (CMEs) and stream interaction regions (SIRs), in shaping the shock acceleration environment for energetic electrons remains not fully understood. In this study, we investigate nine interplanetary shocks observed by the Solar Terrestrial Relations Observatory (STEREO) that are associated with significant MeV electron enhancements, as such enhancements are rarely observed at interplanetary shocks. We combine remote-sensing observations, drag-based modeling, and in-situ measurements to analyze the shock propagation through pre-existing interplanetary structures. Eight of the nine events are associated with a preceding slow or intermediate-speed CME, while six shocks are in-situ observed propagating within preceding ICMEs, indicating that large-scale upstream trapping structures are a common feature of these events. Further analysis identifies three distinct scenarios associated with enhanced electron acceleration: shocks propagating through preceding ICMEs, shock-SIR interactions, and direct injection of flare-accelerated electrons into SIRs. As a representative shock-in-ICME event, the 2012 January 29 low-$β$, quasi-perpendicular shock ($θ_{Bn}\sim87^\circ$) is further investigated using observations together with one-dimensional Monte Carlo test-particle simulations of a shock propagating into a large-scale upstream magnetic loop. The simulation suggests that the upstream loop prolongs electron residence near the shock and substantially enhances acceleration efficiency. These results demonstrate that large-scale interplanetary structures can precondition the upstream magnetic environment, providing favorable conditions for prolonged electron residence and efficient shock acceleration.
