Development and extension of the non-inductive high beta poloidal regime to ITER relevant dimensionless parameters on DIII-D

The high β_p scenario on DIII-D has been extended to higher plasma current and higher β_N in the pursuit of ITER relevant dimensionless parameters. This pursuit is motivated by the fusion gain metric G=β_NH_89p/q₉₅², which is required to be ~0.27 in the ITER Q=5 steady state mission. High β_p experiments on DIII-D maximize this metric in steady-state relevant scenarios through the formation of an internal transport barrier (ITB) and the resulting high confinement and bootstrap fraction. Progress in this ITER-relevant metric will be presented, including details of scenario development and increased understanding of the underlying physics. Inductively-driven DIII-D plasmas with ITBs have achieved high confinement and fusion gain (H_89p=2.8, G=0.21) at either higher current or higher β_N, but increasing both parameters simultaneously has proven difficult. Obstacles such as the fast external kink mode and wall-interactions of counter-streaming ions will be discussed, as will the varying efficacy of RMP-ELM suppression and resistive wall mode feedback. A correlation between core impurities and ITB collapses will also be presented, suggesting that cyclic drops in confinement occur in the absence of adequate particle control.