Highlights from the DIII-D Negative Triangularity Campaign

A dedicated DIII-D negative triangularity (NT) campaign produced over 500 strongly shaped (δ ~ -0.5), diverted NT discharges. These plasmas demonstrate simultaneous access to high normalized current, pressure, density, and confinement – indicating a wide operating space with surprisingly good core stability properties. q₉₅ < 3, b_N ~ 3, Greenwald fractions (f_GW) ~ 1, and H₉₈ ~ 1 are simultaneously observed. The confinement time is found to have a linear dependence on plasma current, significant power degradation, and is reduced at low rotation. Long-duration hybrid-like stationary scenarios with H₉₈~0.95 are accessed. All results are found together with a robustly stable NT edge free from edge-localized modes, despite edge and average pressures comparable to standard DIII-D plasmas without ELMs, and are consistent with a pedestal gradient limited by high-n ballooning modes. Detachment was accessed despite the divertor being open and with short connection length. Together with inherently peaked density profiles, detachment without impurities occurred with f_GW approaching and above unity. Core impurity seeding with Ne, Ar, and Kr enabled access to high radiative-fraction, providing confidence that core-edge integration will be facilitated by reduced exhaust power in NT scenarios.