Speaker
Description
The stability of toroidal magnetic fields in radiative stellar interiors is a key unresolved problem in advancing our understanding of the rotational and chemical evolution of low-mass stars. We perform 3D direct numerical simulations in a spherical geometry to examine the Tayler instability, a kink-type instability of purely toroidal fields expected to occur in stably stratified stellar interiors. The simulations are novel in that they consider a consistent background state derived from magnetohydrostatic equilibrium and explore the combined effect of gravity and thermal diffusion, as well as of fluid viscosity and magnetic resistivity. We trace the entire evolution of the instability from the linear to the nonlinear phase. Our simulations show that stable stratification tames the instability, consistent with findings from a recent global linear stability analysis extending the work of Bonanno & Urpin (2012). Using actual stellar evolution models, our results suggest that toroidal fields in radiative stellar interiors may be only partially affected by Tayler instability. We examine the implications of these findings to better understand the origin of the magnetic fields recently detected in the cores of red giants.
