Overview of Recent DIII-D Experimental Results

DIII-D research fills gaps in scientific understanding for ITER and future reactors. Studies of small ELMs to the first-wall found energy and particle flux decay lengths in the SOL are larger for small ELMs than for type-I ELMs. Strongly shaped negative triangularity discharges show a new edge mode that does not affect global confinement, but may regulate edge transport. An intrinsically grassy ELM regime has been discovered, with low edge collisionality coupled with a high-performance Hybrid core, promising for core-edge integration. Reynolds stress measured in the core using spectroscopy shows that turbulence-driven intrinsic torque successfully reconstructs the observed rotation. Experiments in DIII-D and KSTAR used adaptive and machine learning methods to achieve an optimized 3D field in real-time for ELM suppression with H₈₉β_N/q₉₅²>0.4, up to a 90% increase compared to standard suppression. Experiments show that interactions between large-scale MHD and small-scale drift wave turbulence modulate particle flux in DIII-D wide pedestal quiescent H-mode; a new model quantifies the impact of electron drift wave scattering. A multi-machine database study identified a two-variable, dimensionless stability boundary for the L-mode density limit (LDL), predicting it more accurately than the Greenwald limit. A novel RE mitigation strategy relying on mode-conversion between the launched O-mode polarization and the slow-X-mode was shown to affect the RE population, unlike the standard O and X-mode.