A new dynamic fluid-kinetic model for plasma transport in the plasmasphere

Abstract:

A new dynamic fluid-kinetic (DyFK) model is developed for investigating the plasma transport along a closed flux tube in the plasmasphere by coupling a truncated version of the field line interhemispheric plasma (FLIP) model at altitudes below 800 km and a generalized semi-kinetic (GSK) model above it with an overlapped boundary region (800 km-1100 km) in both hemispheres. The flux tube is allowed to move both radially away from the Earth and azimuthally around the Earth. Ion species O⁺ and He⁺ are for the first time treated as simulation particles in a numerical model for the plasmasphere. The simulation particles are subjected to the parallel electric field, magnetic mirror force, gravity, centrifugal force and Coulomb collisions, as well as possible wave-particle interaction. The effects of ionosphere-plasmasphere coupling on the day-night evolution of the plasmasphere and the relative abundance of O⁺ and He⁺ are studied. Simulations are also conducted to investigate the influence of wave-particle interaction on the field-aligned density distributions of ions (O⁺/ H⁺/ He⁺) and their velocity distributions.