Magnetic buoyancy instabilities in stellar interiors

Magnetic buoyancy instabilities can occur for horizontal magnetic fields varying with depth, which ultimately arise because such a field can support a heavy gas by virtue of the pressure it exerts. These instabilities have been studied in both the linear and nonlinear regimes for a number of years. However, many unsolved problems remain regarding both the linear and nonlinear properties of the instability. Recently, a set of asymptotically-reduced models, that are more amenable to computation and analysis than the fully compressible system, have been derived that describe magnetic buoyancy instabilities in certain parameter regimes. The linear properties of magnetic buoyancy instabilities have not been explored (at all or fully) in several of these models previously. In this project we will first explore the linear properties of magnetic buoyancy instabilities in several of these reduced models, before turning to simulate their nonlinear evolution. It is known that in certain parameter regimes magnetic buoyancy instabilities are double-diffusive, and the nonlinear evolution can lead to layering in the field and density profiles. These issues, and the resulting turbulent transport properties, will be explored with numerical simulations with the goal of understanding their role in stellar and planetary interiors.