Study of Spatiotemporal Development of Global Distribution of Magnetospheric ELF/VLF Waves Using Ground‐Based and Satellite Observations, and RAM‐SCB Simulations, for the March and November 2017 Storms
Study of Spatiotemporal Development of Global Distribution of Magnetospheric ELF/VLF Waves Using Ground‐Based and Satellite Observations, and RAM‐SCB Simulations, for the March and November 2017 Storms
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DOI：
10.1029/2020ja028216
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发表时间：
2021-02
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通讯作者：
Yuhei Takeshita;K. Shiokawa;Y. Miyoshi;M. Ozaki;Y. Kasahara;S. Oyama;M. Connors;J. Manninen;V. Jordanova;D. Baishev;A. Oinats;V. Kurkin
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作者：
Yuhei Takeshita;K. Shiokawa;Y. Miyoshi;M. Ozaki;Y. Kasahara;S. Oyama;M. Connors;J. Manninen;V. Jordanova;D. Baishev;A. Oinats;V. Kurkin
磁层极低频/极低频（ELF/VLF）波通过波粒相互作用在磁层中高能电子的加速和损失中发挥着重要作用。有必要了解磁层ELF/VLF波的时空发展，以定量估计波粒相互作用的影响，这是一个尚未完全了解的全球过程。我们使用位于极光下纬度的6个PWING地面站、地球空间和RBSP卫星中的太阳辐射和辐射探测、POES/MetOp卫星和RAM-SCB模型研究了磁层ELF/VLF波的时空发展，重点关注2017年3月和11月由太阳风中的共转相互作用区域驱动的风暴。我们的结果表明，ELF/VLF波增强的纵向范围从午夜到早晨和日面与亚暴电子注入。在风暴恢复的主要阶段到早期阶段，我们在黎明扇区观测到从2000年到2012年MLT的连续ELF/VLF波。这种广泛的范围似乎是由频繁发生的亚暴造成的。波区向东扩展与从夜面注入的源电子漂移有关。我们还观察到昼侧ELF/VLF波增强，可能是由磁层压缩太阳风驱动，在MLT范围内至少5小时。地面观测往往不会在午夜后的扇区观测到ELF/VLF波，尽管其他方法清楚地表明了波的存在。这可能是由于波的朗道阻尼，等离子体密度管道结构的缺失，和/或午夜后电离层的极光电离增强。
Magnetospheric Extremely Low‐Frequency/Very Low‐Frequency (ELF/VLF) waves have an important role in the acceleration and loss of energetic electrons in the magnetosphere through wave‐particle interaction. It is necessary to understand the spatiotemporal development of magnetospheric ELF/VLF waves to quantitatively estimate this effect of wave‐particle interaction, a global process not yet well understood. We investigated spatiotemporal development of magnetospheric ELF/VLF waves using 6 PWING ground‐based stations at subauroral latitudes, Exploration of energization and Radiation in Geospace and RBSP satellites, POES/MetOp satellites, and the RAM‐SCB model, focusing on the March and November 2017 storms driven by corotating interaction regions in the solar wind. Our results show that the ELF/VLF waves are enhanced over a longitudinal extent from midnight to morning and dayside associated with substorm electron injections. In the main to early storm recovery phase, we observe continuous ELF/VLF waves from ∼0 to ∼12 MLT in the dawn sector. This wide extent seems to be caused by frequent occurrence of substorms. The wave region expands eastward in association with the drift of source electrons injected by substorms from the nightside. We also observed dayside ELF/VLF wave enhancement, possibly driven by magnetospheric compression by solar wind, over an MLT extent of at least 5 h. Ground observations tend not to observe ELF/VLF waves in the post‐midnight sector, although other methods clearly show the existence of waves. This is possibly due to Landau damping of the waves, the absence of the plasma density duct structure, and/or enhanced auroral ionization of the ionosphere in the post‐midnight sector.