三维试验粒子轨道法在磁层粒子全球输运中的应用

根据磁层粒子动力学理论, 通过偶极磁场模型验证利用三维试验粒子轨道方法模拟近地球区(r < 8R_e)带电粒子运动特征的可靠性. 在此基础上, 以太阳风和磁层相互作用的全球MHD模拟结果为背景, 利用三维试验粒子轨道方法, 对非磁暴期间南向行星际磁场背景下太阳风离子注入磁层的情形进行数值模拟, 并对北向行星际磁场背景下太阳风离子注入极尖区以及内磁层的几种不同情形进行了单粒子模拟. 模拟结果反映了南向和北向行星际磁场离子向磁层的几种典型输入过程, 揭示出行星际磁场南向时太阳风粒子在磁层内密度分布的晨昏不对称性以及其在磁鞘和磁层内的大致分布, 并得出统计规律. 模拟结果与理论预测和观测结论相一致, 且通过数值模拟发现, 行星际磁场北向时靠近极尖区附近形成的非典型磁镜结构对于能量粒子经由极尖区注入环电流区域过程有重要的影响和作用. 

Trajectory Method of 3D Test Particles in Global Transport in Magnetosphere

Based on the theory of magnetospheric particle dynamics and the trajectory method of 3D test particles, we firstly verified charged particles' dynamic characters under a dipole field model for the inner magnetosphere situation (r < 8R_e). Then, using a global MHD model as the magnetospheric background, the trajectory method of 3D test particles is employed to investigate the injection of solar wind ions into the magnetosphere during the southward IMF, and to simulate several different typical situations of the injection of the particle into the cusp region during the northward IMF. The simulation results not only reveals the possible processes of the particle injection into the cusp region for northward IMF, but also indicates the general distribution of the particles originally from the solar wind in the magnetosheath and magnetosphere, and the dawn-dusk asymmetry of the particles' density during the southward IMF. The simulation results are coincident with the theory and observation of magnetospheric dynamics. And for the first time, it is indicated by numerical simulation that an atypical magnetic mirror near the polar cusp region plays an important role in the particles' injection from the cusp region to ring current region during northward IMF.