Slot region electron loss timescales due to plasmaspheric hiss and lightning‐generated whistlers
Slot region electron loss timescales due to plasmaspheric hiss and lightning‐generated whistlers
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DOI：
10.1029/2007ja012413
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发表时间：
2007-08
影响因子：
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通讯作者：
N. Meredith;R. Horne;S. Glauert;R. R. Anderson-R.
中科院分区：
文献类型：
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作者：
N. Meredith;R. Horne;S. Glauert;R. R. Anderson-R.
[1]地球辐射带中的高能电子(E>；100keV)与各种哨声模波发生多普勒频移回旋共振相互作用，导致俯仰角散射和随后的大气损失。在这项研究中，我们评估了等离子体层嘶嘶声和闪电产生的哨声在缝隙区域和更远的地方的相对重要性。电子损失时间尺度是使用离子和电子的俯仰角和能量扩散(PADIE)代码以及基于CRRES观测的波功率谱分布的全球模型来确定的。我们的结果表明，在小波法向和中波法线方向传播的等离子体层嘶嘶声在缝隙区域和更远的地方是一个重要的散射介质。相反，在大波法向角传播的等离子体层嘶嘶声和闪电产生的哨声对辐射带损失没有显著贡献。在狭缝区中心(L=2.5)，等离子体层嘶嘶声以小波法向和中波法角传播的2 MeV电子的损失时间为1-10天，这与最近的太阳反常和磁层粒子探测器的观测结果一致。空间波动导致等离子体层嘶嘶声的产生，从而导致缝隙区域的形成。在活动期，在3.5keV；L 4.0区，由于等离子体嘶嘶声引起的损失可能发生在1天或更短的时间尺度上，能量范围很广，200keV；E<；1 MeV。因此，在磁扰动期内，等离子体层的嘶嘶声也可能是外辐射带内部区域的一个重要的损失过程。
[1] Energetic electrons (E > 100 keV) in the Earth's radiation belts undergo Doppler-shifted cyclotron resonant interactions with a variety of whistler mode waves leading to pitch angle scattering and subsequent loss to the atmosphere. In this study we assess the relative importance of plasmaspheric hiss and lightning-generated whistlers in the slot region and beyond. Electron loss timescales are determined using the Pitch Angle and energy Diffusion of Ions and Electrons (PADIE) code with global models of the spectral distributions of the wave power based on CRRES observations. Our results show that plasmaspheric hiss propagating at small and intermediate wave normal angles is a significant scattering agent in the slot region and beyond. In contrast, plasmaspheric hiss propagating at large wave normal angles and lightning-generated whistlers do not contribute significantly to radiation belt loss. The loss timescale of 2 MeV electrons due to plasmaspheric hiss propagating at small and intermediate wave normal angles in the center of the slot region (L = 2.5) lies in the range 1–10 days, consistent with recent Solar Anomalous and Magnetospheric Particle Explorer (SAMPEX) observations. Wave turbulence in space, which is responsible for the generation plasmaspheric hiss, thus leads to the formation of the slot region. During active periods, losses due to plasmaspheric hiss may occur on a timescale of 1 day or less for a wide range of energies, 200 keV < E < 1 MeV, in the region 3.5 < L < 4.0. Plasmaspheric hiss may thus also be a significant loss process in the inner region of the outer radiation belt during magnetically disturbed periods.