Instability of a pinch surrounded by a resistive wall

A pinch configuration which is stabilized by the flow of force-free currents in the outer region and by the presence of an ideally conducting wall becomes unstable if the wall is made slightly resistive. Growth rates for the instability are derived, and it is shown that this instability need not be a limiting factor for thermonuclear experiments, provided that the equilibrium parameters are carefully chosen and that it is possible to operate at the usual high pinch densities. Limitations do arise if the plasma density is reduced.