Improve core-edge integration with X-point radiator (XPR) operation scenario
2025 Research Campaign, Core-Edge Integration
Purpose of Experiment
This experiment aims to explore the X-point radiator (XPR) regime as a pathway to core-edge integration in tokamak plasmas. The focus is on achieving a highly radiative divertor while maintaining high confinement and suppressing Edge Localized Modes (ELMs). The XPR scenario is particularly promising for future fusion power plants (FPPs) as it enables operation with no or reduced ELMs, detached divertors, and high radiation fractions while preserving acceptable confinement levels. DIII-D’s capabilities including flexible divertor configurations, comprehensive diagnostics and the presence of the carbon wall offer key insights into the physics of this regime complementing other international studies in metal-wall tokamaks. Integration of the XPR regime with compact radiative divertors (CRD) where the target plates are placed close the X-point will be assessed as well. This is of particular importance for reactor-scale plasmas since it offers increased volume of the confined plasma and space for breeding blankets. The physics interpretation of the experiments will leverage a unique new capability, the SICAS modeling framework which couples SOLPS-ITER and ASTRA-STRAHL (developed under Casali DOE Early Career Award) which now enables the self-consistent treatment of main and impurity transport from the divertor target to the core. This modeling capability is critical for understanding XPR physics and its implications for future reactors.