Complex magnetohydrodynamic bow shock topology in field-aligned low-b flow around a perfectly conducting cylinder

Two-dimensional ideal magnetohydrodynamic ~MHD! simulations are presented that demonstrate several novel phenomena in MHD shock formation. The stationary symmetrical flow of a uniform, planar, field-aligned, low-b and superfast magnetized plasma around a perfectly conducting cylinder is calculated. The velocity of the incoming flow is chosen such that the formation of fast switch-on shocks is possible. Using a time marching procedure, a stationary bow shock is obtained, composed of two consecutive interacting shock fronts. The leading shock front has a dimpled shape and is composed of fast, intermediate and hydrodynamic shock parts. A second shock front follows the leading front. Additional intermediate shocks and tangential discontinuities are present in the downstream part of the flow. The intermediate shocks are of the 1–3, 1–4, 2–4 and 152–354 types. This is a confirmation in two dimensions of recent results on the admissibility of these types of shocks. Recently it has also been shown that the 152–354 shock, embedded in a double compound wave, is present in the analytical solution of some planar one-dimensional MHD Riemann problems. This MHD flow with interacting shocks may have applications for some observed features of fast solar Coronal Mass Ejections and other phenomena in low-b space plasmas. © 1998 American Institute of Physics. @S1070-664X~98!00611-9#