Statistics of Multi‐MeV Electron Drift‐Periodic Flux Oscillations Using Van Allen Probes Observations
Statistics of Multi‐MeV Electron Drift‐Periodic Flux Oscillations Using Van Allen Probes Observations
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DOI：
10.1029/2022gl097995
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发表时间：
2022-03
影响因子：
5.2
通讯作者：
Hong Zhao;T. Sarris;Xinlin Li;Isabella G. Huckabee;D. Baker;A. Jaynes;S. Kanekal
中科院分区：
文献类型：
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作者：
Hong Zhao;T. Sarris;Xinlin Li;Isabella G. Huckabee;D. Baker;A. Jaynes;S. Kanekal
在地球辐射带中观察到的多MeV电子漂移周期性通量振荡表明这些辐射带核心种群的径向传输和扩散/扩散。使用多年的货车艾伦探测器的观测，进行统计分析，以了解这一现象的特点。结果表明，大多数这些通量振荡的结果与宽带超低频（ULF）波的共振相互作用，是正在进行的径向扩散的指标。在高太阳风速度/动压和地磁活跃时期，通量振荡的发生频率较高;然而，在轻度至中度太阳风/地磁条件下，仍然观察到大量的通量振荡。在不同的地磁活动下，低L-壳层（L 3−4 ${L}^{\ast }\sim 3-4$）的出现频率也最高（高达30%），这表明即使在地磁平静期，低L-壳层也普遍存在宽带ULF波和径向扩散，并显示电子相空间密度径向梯度在形成漂移周期通量振荡中的关键作用。
Multi‐MeV electron drift‐periodic flux oscillations observed in Earth's radiation belts indicate radial transport and energization/de‐energization of these radiation belt core populations. Using multi‐year Van Allen Probes observations, a statistical analysis is conducted to understand the characteristics of this phenomenon. The results show that most of these flux oscillations result from resonant interactions with broadband ultralow frequency (ULF) waves and are indicators of ongoing radial diffusion. The occurrence frequency of flux oscillations is higher during high solar wind speed/dynamic pressure and geomagnetically active times; however, a large number of them were still observed under mild to moderate solar wind/geomagnetic conditions. The occurrence frequency is also highest (up to ∼30%) at low L‐shells ( L∗∼3−4 ${L}^{\ast }\sim 3-4$ ) under various geomagnetic activity, suggesting the general presence of broadband ULF waves and radial diffusion at low L‐shells even during geomagnetically quiet times and showing the critical role of the electron phase space density radial gradient in forming drift‐periodic flux oscillations.