Propagation of the shock wave through the magnetic helmet-type region

This paper presents the numerical simulation of the evolution of shock wave propagating through the magnetic helmet streamer region and further out along the current sheet. It was obtained by using a set of complete projected-characteristic boundary conditions at the inner (1.1 R_s) and outer (62 R_s) boundaries in the solar meridian. Main results reveal that (1) the convection effect of the background wind speed on the propagation of shock wave is significant, especially in the range of ≤60 R_s; (2) a dip of flow speed is formed in the magnetic helmet region and after that, it is weakened in the current sheet region; (3) two high-speed belts appear near the two sides of the magnetic helmet when this is stretched outward; (4) a high-density ring displaces behind the shock surface and could be torn when it moves from the magnetic helmet into the current sheet region.