Over the hours of 05:00–09:00 UT on 8 June 2001, the extreme ultraviolet (EUV) instrument on board the IMAGE satellite observed a shoulder-like formation in the morning sector and a post-noon plume-like structure. The plasmapause formation is simulated using the test particle model (TPM), based on a drift motion theory, which reproduces various plasmapause structures and evolution of the shoulder feature. The analysis indicates that the shoulder is created by sharp reduction and spatial non-uniformity in the dawn–dusk convection electric field intensity. The TPM-modeled event is found to develop an initial pre-dawn asymmetric bulge that becomes a shoulder as a result of increased “corotation” rate with an increasing L-shell that is preceded by localized outward convection. The shoulder structure rotates sunward and develops into a single- or double-plume structure during an active time period in simulation.

中文翻译：

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等离子体层肩结构形成的新视角和解释

在 2001 年 6 月 8 日世界标准时间 05:00-09:00 的几个小时内，IMAGE 卫星上的极紫外 (EUV) 仪器在早晨扇区观测到肩状地层和午后羽状结构。使用基于漂移运动理论的测试粒子模型 (TPM) 模拟等离子层的形成，该模型再现了各种等离子层结构和肩部特征的演变。分析表明，肩峰是由黎明-黄昏对流电场强度的急剧减少和空间非均匀性造成的。发现 TPM 模拟事件会发展出一个初始的黎明前不对称隆起，由于“共转”率增加，L 壳层增加，然后局部向外对流，该隆起变成了肩部。