Variation in crossover frequency of EMIC waves in plasmasphere estimated from ion cyclotron whistler waves observed by Van Allen Probe A
Variation in crossover frequency of EMIC waves in plasmasphere estimated from ion cyclotron whistler waves observed by Van Allen Probe A
复制标题
根据 Van Allen 探针 A 观测到的离子回旋口哨声波估计的等离子体层中 EMIC 波交叉频率的变化
DOI：
10.1002/2015gl066893
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发表时间：
2016
影响因子：
5.2
通讯作者：
and C. A. Kletzing
中科院分区：
文献类型：
--
作者：
Matsuda;S.;Y. Kasahara;and C. A. Kletzing
我们报告了范艾伦探测器 A 观测到的 H+ 波段离子回旋口哨声传播的变化。离子回旋口哨声是由闪电口哨声模式转换产生的 EMIC（电磁离子回旋口哨声）波之一。交叉频率是离子回旋口哨的一个重要频率，它是局部重离子成分变化的函数。我们对电磁场仪和综合科学仪获得的波形数据进行了调查，发现在海拔572公里至5992公里的范围内观测到了3461个H+带离子回旋哨声。主要发现是，观测到的事件的交叉频率随着海拔的增加而降低。这些结果支持总重离子密度随着海拔的增加而降低的假设。此外，在所有观察到的事件中，96% 的交叉频率都超过了 ，这表明 EMIC 色散关系包含大约 的频率间隙。
We report variations in the propagation of the H+band ion cyclotron whistlers observed by Van Allen Probe A. Ion cyclotron whistlers are one of the EMIC (electromagnetic ion cyclotron) waves generated by mode conversion from lightning whistlers. Crossover frequency is an important frequency for the ion cyclotron whistlers, which is a function of the variations in the local heavy‐ion composition. We surveyed waveform data obtained by the Electric and Magnetic Field Instrument and Integrated Science instrument and found that 3461 H+band ion cyclotron whistlers were observed from 572 km to 5992 km in altitude. The main finding is that the crossover frequencies of the observed events decreased with increasing altitude. These results support the hypothesis that the total heavy‐ion density decreases with increasing altitude. Furthermore, in 96% of all observed events, the crossover frequencies exceeded , which suggests that the EMIC dispersion relation contains a frequency gap of around .