ELM Suppression in DIII-D ITER-like Plasmas Using n=2 Magnetic Perturbations

A robust window of edge localized mode (ELM) suppression was observed at elevated magnetic safety factor ($q_{95}\approx$ 4.1) in ITER-like plasmas with even parity n=2 resonant magnetic perturbation (RMP) using the internal I-coils. Variation of the upper and lower I-coil phasing was used to explore the importance of pitch alignment vs kink alignment for ELM suppression. Both the pedestal density and ELM suppression were strongly dependent on I-coil phasing and a large variation in the plasma response amplitude was measured on multiple diagnostics. Surprisingly, toroidal rotation of the even parity n=2 RMP led to the loss of ELM suppression, indicating that components of the residual error field orthogonal to the kink mode may be important near the threshold for ELM suppression.\par