Local measurements of screening currents driven by applied RMPs on TEXTOR

In order to understand the mechanism by which resonant magnetic perturbations (RMPs) mitigate or suppress edge-localized modes, it is necessary to understand the plasma response to the application of RMPs. TEXTOR's fast movable Mirnov probe can provide direct measurements of the plasma response to RMPs applied using the dynamic ergodic divertor. The effect of toroidal plasma rotation is investigated, and a change in the phase of the plasma response at certain values of rotation is found. Jumps in the phase of the magnetic field are found to occur on resonant surfaces, indicating the formation of screening currents on these surfaces. The first observations of screening currents on multiple surfaces are presented, and the transition from screening to field penetration with increasing strength of the applied RMP field is observed.