Building the Fusion Physics Foundation for an FPP and ITER at DIII-D*

The DIII-D Program is well poised to investigate and solve multiple challenges to fusion energy development and to optimize performance via a highly flexible, extremely well-diagnosed, and high-powered advanced tokamak. The program is exploring new divertor geometries and wall materials to improve core-edge integration by closing the gap toward high separatix density, high neutral opacity and low pedestal collisionality. Techniques are being developed to lower the L-H power threshold and enable ELM mitigation to support ITER’s hydrogen phase. New methods of off-axis current-drive to tailor the q-profile via ECH, Helicon and LHCD for quasi-steady operation are being evaluated and applied. A sophisticated and expanding set of plasma profile, neutral particle, boundary and fluctuation diagnostics coupled with machine learning capabilities ensures comprehensive exploration of complex behavior and nonlinear interactions between magnetohydrodynamics, energetic particle-driven modes and turbulence to validate models and nonlinear simulations of core transport and confinement, pedestal structure, MHD, and boundary behavior. The program is simultaneously developing novel scenarios, such as Negative Triangularity-shaped plasmas, to achieve high-normalized density, pressure and confinement.