The stability of Prendergast magnetic fields

ABSTRACT Convection in massive main-sequence stars generates large-scale magnetic fields their cores that persists as they evolve up the red giant branch. The remnants of these may take form Prendergast field, a combination poloidal and toroidal field components are expected to stabilize each other. Previous analytic numerical calculations did not find any evidence for instability over short time-scales. In this paper, we present simulations which show long time-scale, linear field. We be robust changes boundary conditions it is stabilized by strong stable stratification. resistive instability, growth rate has power-law dependence on resistivity, decreases resistivity decreases. estimate extrapolating power law stellar values resistivity. sufficiently rapid destabilize time-scales shorter than evolution indicating good model use studies stars.