A NUMERICAL SIMULATION ON THE EXPANSION OF STRONG MAGNETIC FIELD STRUCTURE IN THE INTERPLANETARY SPACE

This paper studies the expansion effects of strong magnetic field structure (SMFS) in interplanetary space (from 18 R_s to 240 R_s). Simulation results show that the main body of SMFSis typically with a strong magnetic field, low β, high μp, μk, low temperature and low density, but high temperature and density existing in the front and rear of the structure; expansion of SMFSresults in the saw-tooth profile of radial velocity; expansion velocity of SMFSobviously depends on the strength of magnetic field; there is almost no relation between propagation velocity of the structure center and the strength of magnetic field when SMFSis motionless relative to the inner boundary; the s ruoture can intensify (weaken) the compression to the plasma in the front (rear) of the structure when SMFSmoves relating to the inner boundary. The expansion of SMFScan generate a typical profile of magnetic cloud.