Shielding of resonant magnetic perturbations by rotation

Magnetic perturbations that drive islands are shielded from a rotating plasma by either a torque limit or an equilibrium limit. ?he physics of the shielding is given in a simple slab model along with the mechanism by which the shielding currents are maintained. Shielding currents in st channel of width Delta are damped by a resistance eta/Delta with eta the resistivity. If an island is shielded in a nearly ideal plasma, eta/Delta = (mu(0)/pi)V(pA)M(p)(2) with the V-pA the poloidal Alfven speed, M(p) = upsilon(perpendicular to)/V-pA, and upsilon(perpendicular to) the speed of the cross-field how at the resonance surface. (C) 1996 American Institute of Physics.