Electron butterfly distribution modulation by magnetosonic waves
Electron butterfly distribution modulation by magnetosonic waves
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DOI：
10.1002/2016gl068161
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发表时间：
2016-04
影响因子：
5.2
通讯作者：
A. Maldonado;Lunjin Chen;S. Claudepierre;J. Bortnik;R. Thorne;H. Spence
中科院分区：
文献类型：
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作者：
A. Maldonado;Lunjin Chen;S. Claudepierre;J. Bortnik;R. Thorne;H. Spence
蝶形俯仰角分布被观察为以αeq=90°为中心的电子的正常分布中的下降。在风暴期间，形成的蝴蝶分布的夜侧磁层已被归因于L壳分裂结合磁层顶阴影和强大的正径向通量梯度。它已被证明，这种分布可以由组合合唱和磁声波散射，其中两个波一起工作，但在不同的本地时间。在我们的研究中提出的是2013年8月21日的一个事件，使用货车艾伦探测器测量，其中蝴蝶分布的形成是由当地磁声相干磁声波强度调制的。从正常的蝴蝶分布的过渡符合磁声波强度上升，而相反的过渡发生时，波强度减弱。我们提出，反弹共振波是负责这种快速调制的基本过程，这是证实了我们的测试粒子模拟。
The butterfly pitch angle distribution is observed as a dip in an otherwise normal distribution of electrons centered about αeq=90°. During storm times, the formation of the butterfly distribution on the nightside magnetosphere has been attributed to L shell splitting combined with magnetopause shadowing and strong positive radial flux gradients. It has been shown that this distribution can be caused by combined chorus and magnetosonic wave scattering where the two waves work together but at different local times. Presented in our study is an event on 21 August 2013, using Van Allen Probe measurements, where a butterfly distribution formation is modulated by local magnetosonic coherent magnetosonic waves intensity. Transition from normal to butterfly distributions coincides with rising magnetosonic wave intensity while an opposite transition occurs when wave intensity diminishes. We propose that bounce resonance with waves is the underlying process responsible for such rapid modulation, which is confirmed by our test particle simulation.