Energetic electron dynamics is highly affected by plasma waves through quasilinear and/or nonlinear interactions in the Earth's inner magnetosphere. In this letter, we provide physical explanations for a previously reported intriguing event from the Van Allen Probes observations, where bursts of electron butterfly distributions at tens of keV exhibit remarkable correlations with chorus waves. Both test particle and quasilinear simulations are used to reveal the formation mechanism for the bursts of electron butterfly distribution. The test particle simulation results indicate that nonlinear phase trapping due to chorus waves is the key process to accelerate electrons to form the electron butterfly distribution within ~30 s, and reproduces the observed features. Quasilinear simulation results show that although the diffusion process alone also contributes to form the electron butterfly distribution, the timescale is slower. Our study demonstrates the importance of nonlinear interaction in rapid electron acceleration at tens of keV by chorus waves.

中文翻译：

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揭示电子蝴蝶分布爆发的形成机理：测试粒子和拟线性模拟

通过地球内部磁层中的准线性和/或非线性相互作用，等离子波会极大地影响高能电子动力学。在这封信中，我们为范·艾伦探针观测中先前报道的有趣事件提供了物理解释，其中数十keV处的电子蝴蝶形分布爆发与合唱波有显着相关性。测试粒子模拟和准线性模拟均用于揭示电子蝴蝶分布爆发的形成机理。测试粒子的仿真结果表明，由合唱波引起的非线性相位俘获是在约30 s内加速电子形成电子蝶形分布并再现观察到的特征的关键过程。拟线性仿真结果表明，尽管仅扩散过程也有助于形成电子蝶形分布，但时间尺度较慢。我们的研究证明了非线性相互作用对于合唱波在数十keV的快速电子加速中的重要性。