Numerical modeling of the convective Kelvin-Helmholtz instabilities of astropauses

Abstract

In this paper we present the numerical modeling results of the problem of the hypersonic stellar wind interaction with fully ionized interstellar medium that moves with respect to the star with supersonic speed. This is the classical problem that has been firstly studied in 1970 by Baranov et al. [1] under the thin layer approximation.In this paper we present results of numerical solutions obtained with high spatial resolution of the numerical grid. The computations were performed by using GPU processors with high-performance parallel programming technology CUDA from NVIDIA. It is shown that the stationary solution depends only on two dimensionless parameters - Mach number in the interstellar medium, M∞, and adiabatic index, γ. The stationary solutions were obtained for different values of M∞ for low and medium resolution of the numerical grids. For the numerical grids of high spatial resolution the Kelvin-Helmholtz instability appears at the tangential discontinuities (both primary and secondary) in the tail part of interaction region. The instability is convective as it should be according to the linear analyses by Ruderman et al. [6]. We explore the instability evolution with increasing resolution of the numerical grid. Effects of the numerical scheme are also studied.