Convection in a rotating cylindrical annulus in the presence of a magnetic field

The effect of radial and azimuthal components of a magnetic field on the convection columns in the fluid filled gap between two cylinders rotating rigidly about their common vertical axis is investigated numerically. The inner cylinder is cooled, the outer one heated such that the buoyancy force driving the convection is provided by the centrifugal force. Bur the analysis applies also in the planetary case a here the effective components of gravity and of the temperature gradient are reversed. Because of conical end surfaces of the annular gap, the convection columns drift relative to the rotating frame of reference. The magnetic field exerts a stabilizing influence on the onset of convection and on the onset of secondary instabilities leading to stationary mean flow convection or to time dependent vacillating convection. Of particular interest are the cases of merging stability regions when double minima of the neutral curve exist.