Hydromagnetics of rotating fluids

Abstract
The author reviews work on the dynamics of a rapidly rotating electrically conducting fluid in the presence of a corotating magnetic field. While the separate action of either rotation or a magnetic field produces strong dynamical constraints, their simultaneous action can result in comparatively weak net constraints and novel phenomena then arise. A systematic account of these phenomena is given and certain applications to natural systems (with emphasis on the dynamics of the Earth's liquid core) are outlined.