Nonlinear two-fluid modeling of plasma response for the RMPs ELMs control in ITER baseline scenarios*

The plasma response of resonant magnetic perturbations (RMPs) for controlling edge-localized modes (ELMs) in ITER baseline scenarios is investigated by combining the toroidal ideal MHD code GPEC and the nonlinear two-fluid MHD code TM1. A number of issues relative to RMP ELM control are investigated, including RMP coils configuration optimization, predicting the density pump-out and q₉₅ windows of ELM suppression. GPEC 2D scans of the relative coil current phasing reveal the optimal phasing for n = 1 to 5. TM1 nonlinear simulations show RMP penetration at the pedestal-foot, which leads to density pump-out with its magnitude scaling as I_RMP^0.5, and it becomes weaker for higher-n RMP. The TM1 simulations also show field penetration at the pedestal top. Simulations by 2D scans of RMP coil current and q₉₅ reveal the accessing q₉₅ windows of ELM suppression for both n = 3 and 4. The predicted q₉₅ windows of ELM suppression for ITER are very similar to the observations in recent tokamaks and the required RMP coil current is within the designed capability. In addition, the simulations indicate that wide q₉₅ windows of ELM suppression may be accessible in ITER by operating n = 4 RMPs.