Stability of ideal and resistive modes in cylindrical plasmas with resistive walls and plasma rotation

The stabilization of cylindrical plasmas by resistive walls combined with plasma rotation is analyzed. Perturbations with a single mode rational surface q = m/n in a finitely conducting plasma are treated by the ''resistive kink'' dispersion relation of Coppi et al. [Sov. J. Plasma Phys. 2, 533 (1976)]. The possibilities for stabilization of ideal and resistive instabilities are explored systematically in different regions of parameter space. The study confirms that an ideal instability can be stabilized by a close-fitting wall and a rotation velocity on the order of resistive growth rates [J. M. Finn, Phys. Plasmas 2, 3782 (1995)]. However, the region in parameter space where such stabilization occurs is very small and appears to be difficult to exploit in experiments. The overall conclusion from the cylindrical plasma model is that resistive modes can readily be wall stabilized, whereas complete wall stabilization is hard to achieve for plasmas that are ideally unstable with the wall at infinity. (C) 1997 American Institute of Physics.