Precipitation Loss of Radiation Belt Electrons by Two‐Band Plasmaspheric Hiss Waves
Precipitation Loss of Radiation Belt Electrons by Two‐Band Plasmaspheric Hiss Waves
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DOI：
10.1029/2020ja028157
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发表时间：
2019-12
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影响因子：
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通讯作者：
Zhaoguo He;Q. Yan;Xiaoping Zhang;Jiang Yu;Yonghui Ma;Yong Cao;J. Cui
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文献类型：
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作者：
Zhaoguo He;Q. Yan;Xiaoping Zhang;Jiang Yu;Yonghui Ma;Yong Cao;J. Cui
2014年1月6日，Van Allen探测器观测到了由低频(频率低于2 kHz的正常HISS)和高频(频率高达10 kHz的本地产生的HISS)组成的两个频段的等离子体层HISS(He等人，2019年，https://doi.org/10.1029/2018GL081578).首次用准线性扩散模拟方法评价了这种双波段等离子体层的电子散射效应。模拟中采用了统计数据中真实的双频段等离子体球的波形特征参数。低频带HISS的节距角扩散速率在节距角αe∼70°处呈现一个最小幅度的“间隙”，这一条件不利于大节角电子向损耗锥的输运。而高频带HISS的扩散速率在αe∼70°处有峰值，填补了低频带HISS扩散速率的“缺口”。实际的波驱动电子PSD演化表明，低频带和高频带的协同作用可以在2天内引起几十到几百keV高能电子的显着沉淀损失。
A two‐band plasmaspheric hiss consisting of a low‐frequency band (normal hiss with the frequency below 2 kHz) and a high‐frequency band (locally generated hiss with the frequency up to 10 kHz) was observed on 6 January 2014 by the Van Allen Probes (He et al., 2019, https://doi.org/10.1029/2018GL081578). The electron scattering effect driven by this kind of two‐band plasmaspheric hiss is evaluated by the quasi‐linear diffusion simulation for the first time. Realistic wave characteristic parameters of the two‐band plasmaspheric hiss from statistics are adopted for driving our simulation. The pitch angle diffusion rates of the low‐frequency band hiss present a “gap” with minimum magnitude at pitch angle αe ∼ 70°, a condition not favoring the transport of large pitch angle electrons toward the loss cone. However, the diffusion rates of the high‐frequency band hiss have peak values at αe ∼ 70°, filling up for the “gap” of the low‐frequency hiss diffusion rates. The realistic wave‐driven electron PSD evolutions demonstrate that the collaborated effect of the low‐frequency band and high‐frequency band hiss can cause significant precipitation losses of energetic electrons of tens to several hundred keV within 2 days.