Electron Microbursts Induced by Nonducted Chorus Waves
Electron Microbursts Induced by Nonducted Chorus Waves
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DOI：
10.3389/fspas.2021.745927
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发表时间：
2021-10
期刊：
影响因子：
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通讯作者：
Lunjin Chen;Xiao‐jia Zhang;A. Artemyev;Liheng Zheng;Z. Xia;A. Breneman;R. Horne
中科院分区：
文献类型：
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作者：
Lunjin Chen;Xiao‐jia Zhang;A. Artemyev;Liheng Zheng;Z. Xia;A. Breneman;R. Horne
微暴是低地球轨道卫星观测到的短暂但强烈的电子沉淀，可能对外辐射带高能电子的损失有很大贡献。它们的起源很可能是由于哨声模式合唱波，这从两者在空间相关性上的强烈重叠得到了证明。尽管以前对合唱波诱导的突发性电子沉淀进行了模拟，但大多数(如果不是全部)都依赖于合唱波是沿着零波法角的场线导引的假设。这种导管仅限于存在细小尺度的等离子体密度不规则的情况。相反，和声波在密度平滑变化的等离子体中以非导管的方式传播，允许波法线逐渐折射远离磁力线。在这项研究中，用实验粒子模拟方法研究了导管和非导管和声与高能电子的相互作用。在两种不同的情景中发现了电子传输的显著差异，并比较了所产生的电子沉淀模式。这种比较对于解释低地球轨道卫星观测到的电子通量变化响应与磁层和声波的相互作用是有价值的。
Microbursts, short-lived but intense electron precipitation observed by low-Earth-orbiting satellites, may contribute significantly to the losses of energetic electrons in the outer radiation belt. Their origin is likely due to whistler mode chorus waves, as evidenced by a strong overlap in spatial correlation of the two. Despite previous efforts on modeling bursty electron precipitation induced by chorus waves, most, if not all, rely on the assumption that chorus waves are ducted along the field line with zero wave normal angle. Such ducting is limited to cases when fine-scale plasma density irregularities are present. In contrast, chorus waves propagate in a nonducted way in plasmas with smoothly varying density, allowing wave normals to gradually refract away from the magnetic field line. In this study, the interaction of ducted and nonducted chorus waves with energetic electrons is investigated using test particle simulation. Substantial differences in electron transport are found between the two different scenarios, and resultant electron precipitation patterns are compared. Such a comparison is valuable for interpreting low Earth-orbiting satellite observations of electron flux variation in response to the interaction with magnetospheric chorus waves.