Performance and Transport in the ARC Tokamak

The performance and transport of the ARC tokamak have been studied using a range of physics-based and first-principles models to determine the anticipated fusion power generation and provide a first glance into the conditions anticipated in the power plant core. A suite of integrated modeling tools (TRANSP, ASTRA, and TORAX) were utilized to study the ARC reference condition. Using TGLF-SAT2 or QualiKiz modeling for the core transport, coupled with an EPED predicted pedestal condition, yields a range of expected fusion power from approximately 900 – 1300 MW. ARC conditions exhibit large sensitivities to input assumptions related to the pedestal (Ti/Te, Pped) and chosen transport model, with up to a 600MW delta in performance obtained within reasonable assumptions. State-of-the-art, nonlinear gyrokinetic profile prediction indicates that Ion Temperature Gradient turbulence dominates the plasma core with the potential impact of Kinetic Ballooning Modes near the plasma axis. Gyrokinetic predictions of performance are lower than physics-based results, due in large part to reduced density peaking relative to empirical scaling - but significant sensitivities to pedestal assumptions remain. A description of the underlying instabilities, predictions of plasma profiles (ne, Te, and Ti), and ARC fusion power will be presented and used to motivate research directions for the under-construction SPARC tokamak.