3-Dimensional Drift Shell Splitting During the Geomagnetic Disturbance

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.