On free boundary instabilities induced by a resistive wall

Abstract

The paper extends and augments earlier research concerning the effect that a finitely conducting wall has on the linear stability of various plasma models. If a plasma is stable to a particular mode when surrounded by a perfect wall but unstable to it when the wall is removed, then theory indicates that surrounding the plasma with an imperfect wall can lead to instability of that mode on the long time constant of the wall. Analysis of this effect requires that the various modes possible be classified as to whether the plasma is regarded as ideal or resistive, and whether the pitch of the perturbation resonates with that of the equilibrium. The effect of both bulk plasma rotation and mode rotation (plasma diamagnetism) on these various modes is discussed.