Prospects for ITER Q=10 operation without harmful core MHD and without harmful ELMs*

The DIII-D program is assessing options for Q=10 equivalent operation without harmful core MHD or harmful ELMs, integrated with ITER-relevant low collisionality and input torque (or rotation). Experiments have yielded robust Q~10 performance either at zero torque in high collisionality ELMing plasmas, or in low collisionality ELM-stable plasmas with finite NBI torque. Two main lines of research are being pursued, distinguished by the ELM control approach: RMP ELM suppression, and QH-mode edge. Various challenges prevent simultaneous achievement of Q=10 performance without ELMs at low collisionality and low rotation. At high collisonality, the core is stable even at low rotation, but RMP suppression appears precluded, and RMP application tends to cause core instabilities in the experiments so far. At low collisionality, both QH-mode and RMP suppression are possible. However, RMP suppression is lost when the torque is reduced from the co-Ip side, while n=1 core modes are destabilized in QH-mode when the torque is reduced from the counter-Ip side. Plans for further progress will be discussed.