Rotating magnetohydrodynamics

It is shown that rotation of a periodic column of magnetohydrodynamic fluid can be stabilized against current-driven instabilities by rotation. The rotation is considered as resulting from a slight departure from overall charge neutrality, and is braked by wall friction (loss of angular momentum to the cylinder wall). Both effects are modelled phenomenologically in the equation of motion, and the emphasis is on their bulk dynamic effects rather than their microscopic kinetic theory origins. Much as rotation is known to stabilize a Navier-Stokes fluid against transverse displacements, it is shown that sufficient rotation will suppress the helical vortices and helical deformations of the current channel that are known to result when the axial current in the column exceeds its stability threshold. (author)