Design and Utilization of SPARC To Address ITEP Gaps for ARC

The SPARC tokamak is expected to begin operation in mid-2025 and be used to inform the design of an ARC pilot plant that can begin operation in the early 2030’s. This will require using SPARC to close known exhaust physics gaps faster than any anticipated timeline for a DOE-led EXCITE facility. SPARC physics and engineering details relevant for addressing ITEP gaps are outlined. The divertor and diagnostic set are designed to test access to and control of detached divertor solutions at pilot-plant relevant unmitigated SOL heat fluxes, q|| ~10 GW/m², in a variety of magnetic geometries. The high-field operating space allows investigation of ELM-less scenarios like I-mode, and pellet-pacing and external coils to produce n=3 RMPs allow for exploration of ELM mitigation and suppression in H-mode. SPARC’s PFCs will use tungsten, and while its total plasma operational life limits understanding of long-term material migration, gaps related to main-chamber erosion mechanisms (C-X, filaments) at pilot-plant relevant pedestal conditions can be closed. The study of burning plasma physics in a fully integrated reactor scenario will be possible if H₉₈ ~ 0.9-1.0 can be sustained in detached, D-T plasmas. No technology barrier is expected to preclude SPARC from achieving this goal.