On the Existence of Ionospheric Feedback Instability in the Earth's Magnetosphere‐Ionosphere System
On the Existence of Ionospheric Feedback Instability in the Earth's Magnetosphere‐Ionosphere System
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地球磁层电离层反馈不稳定性的存在——电离层系统
DOI：
10.1029/2018ja025942
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发表时间：
2018
期刊：
影响因子：
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通讯作者：
Mishin, Evgeny V.
中科院分区：
文献类型：
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作者：
Streltsov, Anatoly V.;Mishin, Evgeny V.
电离层反馈不稳定性（IFI）被认为是极光区和亚极光区大振幅超低频波和小尺度场向电流的主要产生机制之一。Sydorenko和兰金（2017，https：//doi.org/10.1002/2017GL073415）最近挑战了IFI在地球电离层-磁层系统中任何现实地球物理条件下的存在。由于这一结论与四十多年来成功使用IFI解释和预测观测结果的许多理论，数值和实验工作相矛盾，因此值得特别关注。我们表明，这一结论主要是基于Sydorenko和兰金（2017）提出的两轮模拟中使用的特定电离层密度剖面和边界条件，并且该结果的推广是不合理的。自1981年以来，电离层离子和中性粒子之间的碰撞对不稳定性发展的影响已经得到了很好的研究，这些研究表明，它并不能阻止不稳定性的发展。此外，理论和数值计算结果与观测结果的良好一致性毫无疑问地证实了IFI在地球磁层-电离层系统中的存在和意义。
The ionospheric feedback instability (IFI) has been considered one of the main generation mechanisms for large‐amplitude ultralow frequency waves and small‐scale field‐aligned currents in the auroral and subauroral regions for more than 40 years. Sydorenko and Rankin (2017, https://doi.org/10.1002/2017GL073415) have recently challenged the very existence of the IFI for any realistic geophysical conditions in the Earth's ionosphere‐magnetosphere system. Because this conclusion contradicts numerous theoretical, numerical, and experimental works successfully used IFI to explain and predict results from observations for more than four decades, it deserves special attention. We show that this conclusion is mainly based on the specific ionospheric density profile and boundary conditions used in two runs of simulations presented in Sydorenko and Rankin (2017), and the generalization of this result is not justified. The effect of the collisions between ionospheric ions and neutrals on the development of the instability has been well studied since 1981, and these studies demonstrate that it does not prevent the development of the instability. Furthermore, excellent agreement of the theoretical and numerical results with observations verify without doubt the IFI existence and significance in the Earth's magnetosphere‐ionosphere system.