AI 中文总结
本研究通过球坐标下的全球线性MHD波模型，分析低纬度处空腔模式振荡（CMOs），复现相关谐波，验证其由稠密等离子体层形成，对比行星际激波激发的CMOs与地面观测，支持波动夜侧激发后快速传向日侧的结论。
AI 中文摘要
Pi2振荡已被证实与内磁层低纬度处的空腔模式振荡（CMOs）相关，CMOs也可由向日面的行星际激波激发。我们采用球坐标下的全球线性MHD波模型开展研究，该模型可分析赤道纬度处的这类波动。结果显示，模型复现了部分主要的CMOs谐波；稠密等离子体层会形成驻波空腔模式。我们将行星际激波激发的CMOs与中纬度EMMA阵列的地面观测结果进行对比，发现与Pi2脉动观测结果一致：赤道纬度处午夜低高度的压缩模式阿尔文波与正午地面的该类波存在微小相位差，这支持了“这类波在夜侧内磁层被激发后会快速传播至向日侧”的结论。我们还将结果与地面Pi2脉动的夜-昼时间延迟观测结果进行了对比。
英文摘要
Pi2 oscillations have been known to be associated with cavity mode oscillations (CMOs) in the inner magnetosphere at low latitudes. CMOs can also be excited by interplanetary shocks on the dayside. We present results from a global linear MHD wave model in spherical coordinates that allows us to analyse these waves at equatorial latitudes. We see that the model reproduces some of the principal CMO harmonics. The standing wave cavity modes are set up due to a dense plasmasphere. The CMOs associated with interplanetary shocks are compared with ground observations from the EMMA array at mid-latitudes. In accordance with observations of Pi2 pulsations, we also see a small phase difference between compressional mode Alfvén waves at midnight at low altitudes and on the noon ground, both at equatorial latitudes. This supports the finding that upon being excited in the nightside inner magnetosphere, these waves travel quickly around to the dayside. We compare our results to observations of the night-to-day time delay of ground Pi2 pulsations.
Comments22 pages, 10 figures
Journal refJournal of Geophysical Research: Space Physics, 131, e2025JA034346
