能量粒子进入磁层的数值模拟研究

Simulation on the Penetration of Energetic Particles Into the Magnetosphere

来自行星际的能量粒子进入磁层的过程一直是磁层研究的热点,也是空间天气研究关注的焦点之一,而以往的工作大都集中在讨论不同行星际条件下粒子进入磁层的统计规律.本文在T89磁层模式的基础上,建立了太阳能量粒子进入磁层运动的程序,计算了几种不同能量的质子从不同方位角入射到磁层的运动轨迹.模拟结果表明,能量粒子沿着磁力线方向才可能穿越磁层到达地球表面,越偏离这个方向,则越早被反弹.能量越高的粒子进入到地球磁层上空的角度范围越大,但仍然只有沿着磁力线入射的粒子才能到达地球表面.这些结果与理论预言是一致的.

The study on the penetration of interplanetary energetic particles into the magnetosphere, is one of the key problems in magnetospheric and space weather study, Most of the previous works concentrated on the statistical investigation of the penetration of energetic particles into magnetosphere under different interplanetary conditions. In this paper, the new-developed code is used to calculate the trajectories of energetic particles＇ penetration into the magnetosphere based on T89 model with different energies and pitch angles, The preliminary results show that only those particles moving along the magnetic field lines can penetrate and reach the earth＇s surface. The particles will be reflected earlier with larger deviation angle with respect to the magnetic field lines. The particles with higher energies can penetrate into the magnetosphere with larger distribution of the pitch angle, but only those with directions along the magnetic field lines can reach the ground. All these results are in consistent with theoretical predictions.