GLOBAL FLOW SYMMETRY-BREAKING BY THE ANISOTROPIC KINETIC ALPHA-EFFECT

This paper concerns the self-excitation of large-scale flow patterns i n rotating stratified spherical bodies. The Anisotropic Kinetic Alpha- effect due to the small-scale turbulence is included into the mean-fie ld motion equation and the stability to the global now excitations is studied by solving the linear eigenvalue problem. If the magnitude of the AKA-effect exceeds some critical value, the mean-flow instability onsets. The main finding is the preference of nonaxisymmetric flow pat terns with the azimuthal wave number m = 1. The symmetry relative to t he equator depends on the rotation rate and is much less definite. For Taylor numbers up to Ta similar or equal to 10(6), the symmetric flow patterns relative to the equatorial plane are slightly preferred. For faster rotation, the antisymmetric flow has somewhat smaller critical ''dynamo number'' for the excitation.