Unraveling the Formation Region and Frequency of Chorus Spectral Gaps
Unraveling the Formation Region and Frequency of Chorus Spectral Gaps
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DOI：
10.1029/2022gl100385
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发表时间：
2022-09
影响因子：
5.2
通讯作者：
Jinxing Li;J. Bortnik;Wen Li;X. An;L. Lyons;W. Kurth;G. Hospodarsky;D. Hartley;G. Reeves
中科院分区：
文献类型：
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作者：
Jinxing Li;J. Bortnik;Wen Li;X. An;L. Lyons;W. Kurth;G. Hospodarsky;D. Hartley;G. Reeves
本研究解决了两个基本的问题，有关带状合唱波在地球磁层：1）合唱谱隙附近的赤道源区域或传播远离赤道形成？以及2）为什么合唱谱隙通常位于0.5 fce（fce：电子陀螺频率）以下？通过分析货车艾伦探测器的数据，我们证明了合唱谱间隙观察在源区域，合唱波传播在平行和反平行方向的磁场。合唱团的光谱间隙低于0.5 fce与电子平行加速在赤道朗道共振能量以上的能量。我们解释说，最初产生的合唱波迅速各向同性的电子分布通过朗道共振加速，和各向同性发生较高的能量在较高的纬度。各向同性的人口，在返回到磁赤道，导致合唱间隙通常低于0.5 fce抑制波激发。
The present study addresses two basic questions related to banded chorus waves in the Earth’s magnetosphere: 1) are chorus spectral gaps formed near the equatorial source region or during propagation away from the equator? and 2) why are chorus spectral gaps usually located below 0.5 fce (fce: electron gyro‐frequency)? By analyzing Van Allen Probes data, we demonstrate that chorus spectral gaps are observed in the source region where chorus waves propagate both in the parallel and anti‐parallel directions to the magnetic field. Chorus spectral gaps below 0.5 fce are associated with electron parallel acceleration at energies above the equatorial Landau resonant energies. We explain that initially generated chorus waves quickly isotropize the electron distribution through Landau resonant acceleration, and the isotropization occurs for higher energies at higher latitudes. The isotropized population, after returning to the magnetic equator, leads to a chorus gap typically below 0.5 fce by suppressing wave excitation.