Long Wavelength Vortices of Low Frequency Interchange Modes

Abstract

Nonlinear coupled equations describing the low frequency interchange modes in a plasma with small fraction of the hot electron component are derived on the basis of multi-fluid equations. Stationary vortex solutions in a long wavelength limit are obtained in a plasma stabilized by the charge unconvering effect instead of the finite Larmor radius effect. The solution takes a form of a pair of localized vortices, rotating in opposite directions and moving with a constant velocity in direction perpendicular to the magnetic field. Linear dispersion relation is studied in detail. The dispersion relation of vortex, relating the propagation velocity to the core size of vortex is examined for typical parameters in bumpy torus experiments. Consequently, the positive and negative branches of the propagation velocity for the fixed size of vortex are also found.