Addressing the Integrated Tokamak Exhaust and Performance Gap on DIII-D

DIII-D planned upgrades and modifications are designed to address the integrated tokamak exhaust and performance (ITEP) gap for FPP designs and ITER. A series of divertors are planned to challenge the suitability of current tokamak design points for scenario integration. The newly-installed upper divertor has been redesigned to accommodate high triangularity and elongation plasmas to validate improved pedestal pressure along the peeling stability branch at low collisionality and high density. A second Dissipation Focused Divertor (DFD) is under engineering design to test a model for detachment front stability that preserves core confinement using upstream cryopumping based on edge fluid modeling. Finally, a negative triangularity closed, pumped divertor is in a physics design stage to retain high core confinement in detached scenarios. Planned heating power upgrades include an extension of ECH to ten lines totaling up to 7MW, NBI heating powers to 20MW and helicon and LHCD injection of ~1MW each—all together providing access to high β_n, tailored profile control, and higher P_SOL to the divertor addressing density-driven detachment metrics. Additionally, a new wall material, currently being chosen based on community input, is planned for the divertor and main chamber bringing reactor relevant materials to test compatibility with advanced core-edge scenarios.