Tearing mode velocity braking due to resonant magnetic perturbations

The effect of resonant magnetic perturbations (RMPs) on the tearing mode (TM) velocity is studied in EXTRAP T2R. Experimental results show that the RMP produces TM braking until a new steady velocity or wall locking is reached. The braking is initially localized at the TM resonance and then spreads to the other TMs and to the rest of the plasma producing a global velocity reduction via the viscous torque. The process has been used to experimentally estimate the kinematic viscosity profile, in the range 2-40 m(2) s(-1), and the electromagnetic torque produced by the RMP, which is strongly localized at the TM resonance. Experimental results are then compared with a theoretical model which gives a reasonable qualitative explanation of the entire process.