MAGNETOHYDRODYNAMIC DYNAMOS IN ROTATING SPHERICAL-SHELLS

The problem of magnetic field generation by fluid motions driven by th ermal buoyancy in a rotating spherical shell is considered. In extensi on of earlier work on this problem particular attention is devoted to questions of numerical convergence and of sequences of bifurcations. F inite 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 par ameter space of the problem.