Magnetohydrodynamic dynamos in rotating spherical shells

Abstract

The problem of magnetic field generation by fluid motions driven by thermal buoyancy in a rotating spherical shell is considered. In extension of earlier work on this problem particular attention is devoted to questions of numerical convergence and of sequences of bifurcations. Finite amplitude convection and nonlinear dynamo solutions are found at Rayleigh numbers below the critical value for the onset of convection. Chaotic solutions appear to be preferred in large regions of the parameter space of the problem.