磁层中氧离子分布研究

氧离子是地球磁层中的一种重要的离子成分,它来自于电离层,经过在磁层里的输运和加速过程后被注入到环电流,是形成大磁暴的主要离子成分，并且在磁层的动力学过程中有着重要的作用。以往由于受到卫星观测的限制，人们没有办法得到完整的近地磁层内的氧离子分布特征，特别是缺少中纬地区氧离子的信息。Cluster卫星搭载了高质量的粒子和磁场探测仪器，为研究磁层中的离子成分提供了大量可靠的观测数据，它于2009年进行变轨，其轨道倾角逐渐降低，覆盖了所有的纬度，为解决这一问题提供了很好的机遇。本课题计划利用Cluster计划的多颗卫星探测数据对磁层内的氧离子分布进行详细的研究，争取在下面三个方面取得重要进展：（1）氧离子在磁层中的输运过程及其伴随的加速机制；（2）氧离子对磁层内的重联过程的影响；（3）氧离子对内磁层超低频波的影响。

O+ is an important species in the magnetosphere. Oxygen ions upflow from the ionosphere, and are transported and accelerated in the magnetosphere. They are further injected into the ring current and are responsible for the development of major magnetic storms. Oxygen ions also have important effects on many processes in the magnetosphere. However, due to the limitation of in situ measurements, the full distribution of oxygen ion has not been developed, especially for mid-latitude regions. Cluster satellites have provided high-quality measurement of particle and fields in the magnetosphere. Since 2009, Cluster changes its orbit to cover more regions and provides an unique opportunities to analyze three-dimensional distribution of oxygen in the near-Earth magnetosphere. In this project we propose to use Cluster observations to investigate the characteristics of oxygen in the magnetosphere. Specifically, we strive to address the follow objectives: a) Investigation of the transportation and acceleration of oxygen ion in the magnetosphere; b) Investigation of the effect of oxygen ion on magnetic reconnections in the magnetosphere; c) Investigation of the effect of oxygen ion on the ULF waves in the inner magnetosphere.