Cavity Mode Wave Frequency Variation Associated With Inward Motion of the Magnetopause During Interplanetary Shock Compression
Cavity Mode Wave Frequency Variation Associated With Inward Motion of the Magnetopause During Interplanetary Shock Compression
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DOI：
10.1029/2023ja031299
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发表时间：
2023-03
期刊：
影响因子：
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通讯作者：
Dianjun Zhang;Wenlong Liu;Zhao Zhang;Xinlin Li;T. Sarris;J. Goldstein;Rezvov Dmitry
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文献类型：
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作者：
Dianjun Zhang;Wenlong Liu;Zhao Zhang;Xinlin Li;T. Sarris;J. Goldstein;Rezvov Dmitry
腔模波是指在不同磁层边界之间捕获或径向驻留的快模波，已在理论上得到发展，并在观测研究中得到报道。在这项研究中，我们提出了2017年8月31日在等离子体轨道外观察到的行星际激波（IPS）诱导的腔模波事件。方位电场和压缩磁场之间的90°相位延迟表明，IPS触发的快模波是驻波，可能径向捕获在磁层顶和等离子体层顶之间的空腔中。利用货车艾伦探测器B位于等离子体层顶外的位置和南北极研究所地面高纬阵列在正午扇区的位置，认为观测到的压缩波与空腔模有关，其内边界位于等离子体层顶，外边界位于磁层顶。压缩磁场的小波谱的峰值频率从10.5增加到12.5 mHz，这与理论计算的腔体本征频率在IPS前后一致。我们还提供了第一个证据，腔模的峰值频率增加，由于向内运动的磁层顶在IPS压缩。
A cavity mode wave, referring to a trapped or radially standing fast mode wave between different magnetospheric boundaries, has been developed in theory and reported in observation studies. In this study, we present an interplanetary shock (IPS)‐induced cavity mode wave event observed outside the plasmasphere on 31 August 2017 with multispacecraft measurements. The phase delay of 90° between the azimuthal electric field and compressional magnetic field indicates that the fast‐mode wave triggered by the IPS is a standing wave, presumably radially trapped in the cavity between the magnetopause and plasmapause. Taking advantage of the location of Van Allen Probe B spacecraft right outside the plasmapause and the Arctic and Antarctic Research Institute ground‐based high‐latitude array mapped in the noon sector, it is suggested that the observed compressional wave associates to cavity mode with its inner boundary at the plasmapause and its outer boundary at the magnetopause. The peak frequency of the wavelet spectrum of the compressional magnetic field increases from 10.5 to 12.5 mHz, which is consistent with the theoretically calculated cavity eigenfrequencies before and after the IPS. We also provide the first evidence that the peak frequency of the cavity mode increases due to the inward motion of the magnetopause during IPS compression.