Plasma Response to Static and Single-Phase Oscillating Resonant Magnetic Perturbations(^* )

Plasma response to ( m=2 ), ( n=1 ) resonant magnetic perturbations(RMPs) is studied using a modular, single-phase saddle coil set. In plasmas with no pre-existing MHD activity, observed driven plasma response to static and oscillating RMPs is paramagnetic. Comparison of the observed response is made with theories of plasma healing and driven reconnection by Boozer(A.H. Boozer, Phys. Fluids, (27), 2055, 1984.), Fitzpatrick(R. Fitzpatrick, Nuclear Fusion, (33), 1049, 1993.) and Jensen(T.H. Jensen et al. Phys. Fluids B, , 1239, 1993). In plasmas with pre-existing MHD, saturated modes are observed to frequency-lock to applied variable frequency oscillating RMPs. Mode frequency dynamics, temporal locking distortions and lock-in torque are used to characterize the observed plasma response as a function of mode amplitude and frequency difference with the applied RMP field. (^*)Work supported by US DOE Grant DE--FG02--86ER--53222