Hot Plasma Effects on Electron Resonant Scattering by Electromagnetic Ion Cyclotron Waves
Hot Plasma Effects on Electron Resonant Scattering by Electromagnetic Ion Cyclotron Waves
复制标题
DOI：
10.1029/2022gl099229
复制
发表时间：
2022-05
影响因子：
5.2
通讯作者：
M. F. Bashir;A. Artemyev;Xiao‐jia Zhang;V. Angelopoulos
中科院分区：
文献类型：
--
作者：
M. F. Bashir;A. Artemyev;Xiao‐jia Zhang;V. Angelopoulos
电磁离子回旋（EMIC）波的共振散射是地球内磁层中相对论电子损失的最有效机制之一。然而，低空航天器的测量经常表明，沉淀电子的能量范围比基于EMIC波的冷等离子体色散的理论预测更宽。为了解释这种差异，我们研究的EMIC波的扩散率，包括热等离子体效应在其色散关系。利用观测到的离子分布函数，我们研究了热等离子体在宽频率范围内对EMIC波色散的影响。我们开发了热等离子体对EMIC色散的影响的解析方程，并将此模型应用于扩散速率评估。我们发现，热离子效应往往会增加波强度最大值附近频率范围的最小共振能量，但会降低波谱高频部分的最小共振能量。
Resonant scattering by electromagnetic ion cyclotron (EMIC) waves is one of the most effective mechanisms of relativistic electron losses in Earth’s inner magnetosphere. Low‐altitude spacecraft measurements, however, often show that the energy range of precipitating electrons is wider than theoretical predictions based on the cold plasma dispersion of EMIC waves. To explain this discrepancy, we examine the diffusion rates of EMIC waves by including hot plasma effects in their dispersion relation. Using the observed ion distribution functions, we investigate the hot plasma effects on the EMIC wave dispersion for a wide frequency range. We develop analytical equations for hot plasma effects on EMIC dispersion, and apply this model to diffusion rate evaluations. We show that hot ion effects tend to increase the minimum resonant energy for the frequency range around wave intensity maxima, but can decrease the minimum resonant energy for the higher‐frequency part of wave spectra.