Physics and engineering drivers for the mission and design of an EXCITE facility

Compact tokamaks have been proposed as a means of potentially reducing the capital cost of a fusion pilot plant (FPP). However, compact tokamak FPPs with higher magnetic field and reduced major radius and surface area face the challenge of integrating high core confinement, plasma pressure, and high divertor parallel heat flux and wall loading. This integration is sufficiently challenging that construction and operation of an EXhaust and Confinement Integration Tokamak Experiment (EXCITE) has been proposed by the U.S. community to close this integration gap. This presentation will review EXCITE in the context of present and planned facilities and describe recent systems studies and design activities for superconducting steady-state EXCITE facilities. Specific core-edge integration challenges including edge density operating windows and choice of impurities for detached divertor operation, the potential to access turbulence-driven broadening of the scrape-off-layer heat fluxes, and H-mode access and sustainment with high core radiation fraction will be described as a function of facility size and aspect ratio [1].

[1] J.E. Menard, B.A. Grierson, et al, Nucl. Fusion 62 (2022) 036026