Mode Coupling From Kinetic Alfvén Waves to Electron Acoustic Waves in the Topside Ionosphere
Mode Coupling From Kinetic Alfvén Waves to Electron Acoustic Waves in the Topside Ionosphere
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DOI：
10.1029/2020gl091702
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发表时间：
2021-01
影响因子：
5.2
通讯作者：
R. Shi;Jun Liang;B. Ni
中科院分区：
文献类型：
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作者：
R. Shi;Jun Liang;B. Ni
基于漂移动力学模型，研究了动力学阿尔文波（KAWs）在顶侧电离层中的传播和能量转移。我们研究了产生的电子声波（EAWs）的垂直波长和热电子温度的依赖关系。随着垂直波长的减小和热电子温度的升高，KAWs与EAWs的耦合变得越来越重要。除了过渡区外，EAWs的朗道阻尼很强，在过渡区，非线性耗散可能很重要。随着波振幅的增加，当冷电子密度的耗尽与初始背景冷电子密度相当时，所产生的电子声学模式波变得不可持续。这些结果表明，电声模波在动力学尺度上起着重要的作用，在顶侧电离层。
The propagation and energy transfer of kinetic Alfvén waves (KAWs) in the topside ionosphere are investigated based on a drift kinetic model. We examine the dependence of the generation of electron acoustic waves (EAWs) on the perpendicular wavelength and on the hot electron temperature. With decreasing perpendicular wavelength and increasing hot electron temperature, the coupling of KAWs to EAWs becomes increasingly important. The Landau damping of the EAWs is strong except in the transition region, where the nonlinear dissipation can be important. With increasing wave amplitude, the generated electron acoustic mode waves become unsustainable when the depletion of cold electron density is comparable to the initial background cold electron density. These findings indicate that electron acoustic mode waves play an important role at kinetic scales in the topside ionosphere.