Quasi-linear MHD modelling of H-mode plasma response to resonant magnetic perturbations

The plasma response to externally imposed resonant magnetic perturbations (RMPs) is investigated through quasi-linear MHD modelling in the case where the resonant surfaces are located in the pedestal of an H-mode plasma. The pedestal is a particular region regarding the question of plasma response to RMPs because of its strong E × B and electron diamagnetic rotations. It is found that a strong rotational screening takes place in most of the pedestal. The RMPs may, however, penetrate in a narrow layer at the very edge, where the plasma is cold and resistive. The possibility that one harmonic of the RMPs may also penetrate if its resonant surface is at a particular location, close to the top of the pedestal, where the E × B and electron diamagnetic rotations compensate each other, is discussed. Finally, the RMPs are found to produce some additional transport, even though they do not penetrate.