Rapid Frequency Variations Within Intense Chorus Wave Packets
Rapid Frequency Variations Within Intense Chorus Wave Packets
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DOI：
10.1029/2020gl088853
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发表时间：
2020-08
影响因子：
5.2
通讯作者：
X.‐J. Zhang;D. Mourenas;A. Artemyev;V. Angelopoulos;W. Kurth;C. Kletzing;G. Hospodarsky
中科院分区：
文献类型：
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作者：
X.‐J. Zhang;D. Mourenas;A. Artemyev;V. Angelopoulos;W. Kurth;C. Kletzing;G. Hospodarsky
哨声模式的合唱波是地球辐射带中电子加速的原因。然而，目前尚不清楚所观察到的加速度是否仍然可以用准线性理论很好地描述，或者这种加速度是否是由于需要非线性处理的强烈波引起的。在这里，我们进行了全面的统计分析，强烈的低波段合唱波包，以调查波频率变化，包长度和波振幅之间的关系，以及它们的时间变异性。我们发现，15%的波功率进行长包，与低频率扫描率（线性趋势的时间），同意合唱波增长的非线性理论。然而，85%的波功率来自于线性趋势附近具有较大频率变化的短数据包。这些变化的kappa样概率分布与不同波的随机叠加一致，这可能导致非线性共振相互作用的破坏。
Whistler mode chorus waves are responsible for electron acceleration in Earth's radiation belts. It is unclear, however, whether the observed acceleration is still well described by quasi‐linear theory, or if this acceleration is due to intense waves that require nonlinear treatment. Here, we perform a comprehensive statistical analysis of intense lower‐band chorus wave packets to investigate the relationships between wave frequency variations, packet length, and wave amplitude, and their temporal variability. We find that 15% of the wave power is carried by long packets, with low frequency sweep rates (linear trend in time) that agree with the nonlinear theory of chorus wave growth. Eighty‐five percent of the wave power, however, comes from short packets with large frequency variations around the linear trend. The kappa‐like probability distribution of these variations is consistent with random superposition of different waves that could result in a destruction of nonlinear resonant interaction.