合声是分布于磁层中的一种重要的等离子体波。合声可以加速电子，并通过波粒相互作用，将高能电子/相对论电子沉降到底部电离层。由于合声在磁层中高能电子/相对论电子的产生和损失中扮演着重要的角色，因此研究合声的激发机制具有极其重要的意义。夜侧合声的激发往往与亚暴期间高能电子注入有关，但是向日侧合声的激发比较复杂，仍是一个没有解决、具有争论性的问题。本项目拟用THEMIS卫星和Cluster卫星的数据来研究强太阳风动压导致的高能电子Shabansky运动和磁壳漂移分离在合声激发中所起的作用。同时结合POES卫星的观测以及准线性分析方法探索向日侧产生的合声在散射高能电子，以及在磁层-电离层耦合中所起的作用。该研究结果将进一步揭示磁层中合声波的产生机制、及其导致的磁层-电离层耦合过程，从而为磁层、电离层的建模以及空间天气预报提供重要的科学依据。

The chorus waves is one kind of important plasma waves which distribute in the magnetosphere. The chorus waves can accelerate the electrons and precipitate the energetic/relativistic electrons into the low ionosphere due to wave-particle interaction. The chorus waves play important roles in both the emerge and loss of energetic/relativistic electrons, so it is significative to research the excitation mechanism of chorus waves. The excitation of chorus waves in the nightside are often associated with the energetic electron injections during substorms. However, the excitation mechanism of chorus waves in the dayside is more complex, it is still an open question. This project will utilize the data of THEMIS and Cluster satellites to research the role of energetic electron Shabansky orbit and drift shell splitting due to enhancement of solar wind dynamic pressure on the chorus intensification. Additionally, in this project, the particle data from the POES satellites and quasi-linear approach are utilized to study the role of dayside-chorus in electron scattering and coupling between the magnetosphere and ionosphere. The result will further reveal the generation mechanism of chorus in the magnetosphere and the role of chorus in coupling between magnetosphere and ionosphere, so it is helpful to establish the model of magnetosphere/ionosphere and space weather forecasting.