通过土星辐射带小尺度吸收损失结构定量研究对流电场

土星磁层的对流模式及其对辐射带高能电子演化的作用是行星磁层物理学的重要问题之一。本项目将通过分析卡西尼飞船进入土星磁层轨道后的13年观测数据，考察土卫二轨道以内的能量电子小尺度吸收损失结构。项目拟基于轨迹优化方法发展能量电子漂移模型，对小尺度吸收损失结构在土星辐射带中的漂移轨迹进行模拟。通过对模拟结果与观测数据进行比较，构建土卫二轨道以内大尺度对流电场的分布特征。本课题拟进一步分析对流电场在土星辐射带核心区域对相对论电子的加速与输运起到的作用，以及形成对流电场的可能原因。

The convection pattern in Saturnian magnetosphere, and its roles on the evolution of energetic electrons in radiation belts, are among the important questions in planetary magnetospheric physics. Through the survey of 13-years MeV electron measurements from Cassini spacecraft, the microsignatures due to absorption by moons inside Enceladus' orbit are going to be analyzed. The simulation method is going to be developed, based on tracking the bounce-average drifts of energetic electrons and the trajectory optimization theory. The model results will be compared with observations to retrieve the distribution of global convection electric field. The effects of convection electric field will be evaluated on the acceleration and transport of MeV electrons in the core region of radiation belts. The spatial and temporal variations resolved from the analyses may also shed light on the possible origins of the convection electric field.