Numerical simulations of stellar convective dynamos. II - Field propagation in the convection zone

The author presents numerical simulations of nonlinear, three-dimensional, time-dependent, giant-cell stellar convection and magnetic field generation. The velocity, magnetic field, and thermodynamic variables satisfy the anelastic magnetohydrodynamic equations for a stratified, rotating, spherical shell of ionized gas. The interaction of rotation and convection produces a nonlinear transport of angular momentum that maintains a differential rotation in radius and latitude. Magnetic fields are generated by the shearing and twisting effects of the differential rotation and helical motions and are destroyed by eddy diffusion. The simulations are compared with the solar magnetic cycle and it is suggested that, instead of operating in the turbulent convective region, the solar dynamo may be operating at the base of the convection zone.