Compressible Kelvin-Helmholtz instability in supermagnetosonic regimes

We investigate the transition from submagnetosonic to supermagnetosonic regimes in the presence of a sheared flow and density variations typically observed between the solar wind and the Earth's magnetosphere. In particular, we show the possibility of generating quasi-perpendicular magnetosonic shock structures under typical conditions that can be realized at the magnetosphere flanks. Here the Kelvin-Helmholtz instability generates rolled-up, large- scale vortices that propagate along the flanks of the magnetosphere. The shocks are generated by those vortices for which the magnetosonic Mach number turns out to be of the order of unity or larger.