磁扰期间的三维漂移壳分离  

3-Dimensional Drift Shell Splitting During the Geomagnetic Disturbance

作　　者：黄朝艳[1] 徐荣栏[1] 韩建伟[1] 

机构地区：[1]中国科学院空间科学与应用研究中心

出　　处：《空间科学学报》2008年第4期288-294,共7页Chinese Journal of Space Science

基　　金：国家自然科学基金项目资助(40436016)

摘　　要：基于磁层粒子动力学理论,首先对比了计算漂移壳分离的引导中心法和磁力线追踪法,计算表明两种方法的计算结果一致.然后分别采用T89c和T96磁层磁场模式,用磁力线追踪法数值计算了不同初始位置(≤9R_e)、不同初始投掷角、不同K_p指数和不同太阳风压力下,带电粒子的漂移壳分离.计算结果揭示了漂移壳分离随初始位置、投掷角、K_p指数和太阳风压力的变化.其具体特征如下.(1)随着径向距离的增大,漂移壳分离效应愈加显著,由正午出发的粒子将被稳定捕获,而午夜出发的径向距离≥7R_e的部分大投掷角粒子将沿磁层顶逃逸.(2)正午出发的粒子,漂移到午夜时其漂移壳随投掷角减小向外排列;午夜出发的粒子,漂移到正午时其漂移壳随投掷角增大排列;90°投掷角粒子在磁赤道面的漂移壳沿着磁场等值线排列.(3)漂移壳分离随K_p指数和太阳风压力增大变得显著,且随这两种扰动参数的变化特征和趋势是基本相似的.Based on the theory of magnetospheric particle dynamics, the guiding center and magnetic field line tracing methods are used to calculate the drift shell splitting of the particle motion in the radiation belt. The results show that the two methods are the same. Therefore the 3-dimensional drift shell splitting during the geomagnetic disturbances is studied using magnetic field line tracing method. The initial location of the particles is ≤ 9Re with different initial pitch angles. Different magnetic disturbance index Kp and solar wind pressure, corresponding to T89c and T96 magnetic field model, are compared to each other. The results show that drift shell splitting varies with initial position, pitch angles, Kp index and solar wind pressure. The details are： （1） The drift shell splitting is stronger when the radius distance increases. Particles staring from noon will be trapped stably; otherwise, particles starting from night will escape from the magnetopause, when the initial radius distance and pitch angle are large. （2） When the initial pitch angles on the magnetic equatorial plane increase, the drift shell of particles starting from noon align inward, but from night align outward. （3） Drift shell splitting becomes obvious when Kp index or solar wind pressure increase, and the basic character and trend under these two disturbance parameters are the same.

关 键 词：引导中心法 磁力线追踪法 漂移壳分离 

分 类 号：P353[天文地球—空间物理学]