极隙区位于高纬磁中午附近，是地球磁场与行星际磁场直接相连的通道，也是太阳风粒子能够直接进入磁层乃至电离层的唯一区域，在太阳风-磁层-电离层耦合过程中占有重要的地位。极隙区及其附近存在复杂的物质与能量的变换和输运过程，其中最为典型的现象之一是Pc1-2波(0.1-5Hz)，也称为离子回旋波，其激发和传播跟磁场结构、粒子运动和等离子体环境均密切相关。本项目拟利用我国南极中山站和北极黄河站及其附近台站的观测数据，以及Cluster等卫星观测数据，研究极隙区及其附近的Pc1-2波的起源和传播，对比分析其南北极异同，分析地磁场位型和等离子体环境参数以及边界层过程对波激发和传播的影响。由此获得对极隙区结构和动力学过程以及太阳风-磁层-电离层能量耦合过程的新认识。

The cusp is located around the local magnetic noon at the high latitude, acting as a tunnel where the geomagnetic field lines can directly connect with the interplanetary magnetic field, and the solar wind particles can penetrate into the magnetosphere and even the ionosphere, therefore it play a crucial role in the solar wind-magnetosphere-ionosphere coupling processes. The cusp and its vicinity are rich in complicated transformation and transportation for mass and energy, such as the excitation and propagation of the Pc1-2 waves, also called the electromagnetic ion cyclotron waves. The Pc1-2 waves are highly associated with the background magnetic field structure, the activities of the charged particles, and the plasma environment parameters, etc. In this project observations from Chinese Antarctic Zhongshan Station, Chinese Arctic Yellow River Station and the other sites near them, as well as from the four Cluster satellites will be utilized, to investigate the generation and propagation of the Pc1-2 waves near the cusp. The work will focus on the comparison of the wave occurrence and properties between the northern and southern hemispheres, and their dependence on the geomagnetic field configuration and charged particle activities, as well as their relationship with the boundary physical courses near the cusp. This will enhance our knowledge regarding the complicated structure and dynamic course around the cusp and the energetic coupling for solar wind-magnetosphere- ionosphere system.