电子环分布激发的ECH波全球分布和不稳定性及其对辐射带电子的影响

磁层电子由于其分布函数的损失锥特征而表现为电子环分布（在约0.1-10keV附近，电子相空间密度随速度垂直分量的增大而增大），由电子环分布所激发的静电电子回旋谐波（ECH波）可导致高能电子在极光区的沉降损失，从而对辐射带高能电子动力学演化过程产生重要影响。但是ECH波的全球分布特征、不稳定性及对辐射带电子的影响还有待系统深入研究。本项目拟利用THEMIS、Van Allen和MMS等卫星的高精度探测数据。系统性地研究不同地磁活动条件下ECH波及电子环分布在波幅、波频率、环分布峰值及对应能量等方面的全球分布特征，结合观测数据、理论分析与数值模拟研究ECH不稳定性和传播特性，从而深入理解ECH波的全球分布规律，在此基础上研究不同地磁活动条件下ECH波驱动的辐射带电子动力学演化规律，从而有助于为建立一个基于卫星探测结果的，包含ECH波在内多种波模驱动的更精确的辐射带电子动力学模型打下良好的基础。

The loss cone feature of electrons in the magnetosphere appears as an electron ring distribution (the electron phase space density increases with the perpendicular velocity at energies between ~0.1 and 10 keV). Electrostatic electron cyclotron harmonic (ECH) waves generated by the electron ring distribution can produce efficient scattering loss of energetic electrons, which has a significant effect on the dynamics in the outer magnetosphere. However, the global distribution and instability of ECH wave and its effect on electrons in the radiation belt are still to be studied systematically. In this proposal, we shall study the global distribution of ECH waves and electron rings during different geomagnetic activities by using detection data from THEMIS spacecrafts, Van Allen probes and MMS satellites. We shall combine observational data, theoretical analysis and numerical simulation to study instability and propagation characteristics of ECH waves and understand their global distribution. We plan to study the dynamic evolution of energetic electrons driven by ECH waves under different geomagnetic conditions. This work will help to provide a foundation for the development of a more accurate model for dynamic evolution of energetic electrons in the radiation belt driven by various wave modes including ECH waves based on the satellite detection results.