A Bow Shock Flow Containing (Almost) All Types of (‘Exotic’) MHD Discontinuities

Abstract

We present 2D numerical simulations of a planar field-aligned ideal Magnetohydrodynamic (MHD) bow shock flow in a regime where fast MHD switch-on shocks are possible. In this regime, the interaction of the 3 nonlinear waves of the non-strictly hyperbolic MHD system leads to a complicated solution with interacting shocks of different MHD shock type. Fast and slow shocks and tangential discontinuities are present in the flow. Moreover, we clearly identify non-classical intermediate shocks and shocks with a compound structure, which are a manifestation of the non-convex nature of the hyperbolic MHD system. We discuss some numerical problems encountered when high-resolution numerical MHD schemes derived from common Computational Fluid Dynamics approaches are used to simulate this kind of flows. This bow shock flow simulation is extremely simple in setup, but contains a wealth of interacting MHD shocks, which makes it a good new test case for ideal MHD codes. Observations suggest that the MHD shock formation effects of our simulations may occur in processes in the corona of the sun.KeywordsShock FrontTangential DiscontinuitySlow ShockFast ShockHydrodynamic ShockThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.