Magnetohydrodynamic equilibria in barotropic stars

Abstract

Although barotropic matter does not constitute a realistic model for magnetic stars, it would be interesting to con rm a recent conjecture that states that magnetized stars with a barotropic equation of state would be dynamically unstable (Reisenegger 2009). In this work we construct a set of barotropic equilibria, which can eventually be tested using a stability criterion. A general description of the ideal MHD equations governing these equilibria is summarized, allowing for both poloidal and toroidal magnetic eld components. A new nite-di erence numerical code is developed in order to solve the so-called Grad-Shafranov equation describing the equilibrium of these con gurations, and some properties of the equilibria obtained are brie y discussed.