On the dependence of storm time ULF wave power on magnetopause location: Impacts for ULF wave radial diffusion
On the dependence of storm time ULF wave power on magnetopause location: Impacts for ULF wave radial diffusion
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风暴时间 ULF 波功率对磁层顶位置的依赖性：对 ULF 波径向扩散的影响
DOI：
10.1002/2015gl066592
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发表时间：
2015
影响因子：
5.2
通讯作者：
D. Sibeck
中科院分区：
文献类型：
--
作者：
K. Murphy;I. Mann;D. Sibeck
超低频（ULF）波在内磁层高能粒子动力学中起着至关重要的作用。我们研究了在63个日冕物质抛射（CME）驱动和共转相互作用区（CIR）驱动的磁暴期间，磁层顶位置在控制内磁层内ULF波的振幅和穿透力方面的作用。值得注意的是，在磁层顶最压缩的时候，超低频波功率增加，并穿透到最深的L壳层。最有可能的解释是接近能量源，通过太阳风-磁层顶-磁层耦合在较小的体积内积累能量，以及冷等离子体密度变化导致的风暴时间阿尔芬连续体的变化。观测到的ULF波功率始终大于依赖于Kp的统计估计值，特别是在外辐射带的中心。这对辐射带动力学，包括主相损失和风暴时间ULF波径向扩散具有重要意义。
Ultralow frequency (ULF) waves play a crucial role in energetic particle dynamics in the inner magnetosphere. We examine the role of the magnetopause location in controlling the amplitude and penetration of ULF waves within the inner magnetosphere during 63 coronal mass ejection (CME)‐driven and corotating interaction region (CIR)‐driven geomagnetic storms. Significantly, at the time when the magnetopause is most compressed, ULF wave power increases and penetrates to the deepest L shells. Most likely this is explained by proximity to the energy source and accumulation of energy within a smaller volume through solar wind‐magnetopause‐magnetosphere coupling, and changes in the storm time Alfvén continuum resulting from variations in the cold plasma density. The observed ULF wave power is consistently larger than Kp‐dependent statistical estimates—especially in the heart of the outer radiation belt. This has important implications for radiation belt dynamics, including main phase loss and storm time ULF wave radial diffusion.