Ideal magnetohydrodynamic flow around a blunt body under anisotropic pressure

Abstract

The plasma flow past a blunt obstacle in an ideal magnetohydrodynamic (MHD) model is studied, taking into account the tensorial nature of the plasma pressure. Three different closure relations are explored and compared with one another. The first one is the adiabatic model proposed by Chew, Goldberger, and Low. The second closure is based on the mirror instability criterion, while the third depends on an empirical closure equation obtained from observations of solar wind flow past the Earth’s magnetosphere. The latter is related with the criterion of the anisotropic ion cyclotron instability. In the presented model, the total pressure, defined as the sum of magnetic pressure and perpendicular plasma pressure, is assumed to be a known function of Cartesian coordinates. The calculation is based on the Newtonian approximation for the total pressure along the obstacle and on a quadratic behavior with distance from the obstacle along the normal direction. Profiles of magnetic field strength and plasma parameters are presented along the stagnation stream line between the shock and obstacle of an ideal plasma flow with anisotropy in thermal pressure and temperature.