Design of an X-point slot closed divertor for the HL-3 tokamak with SOLPS-ITER

Abstract In this paper, we introduce a novel X-point Slot Closure (XSC) divertor developed for the HL-3 tokamak. The XSC divertor combines the benefits of W-shaped, V-shaped, Small Angle Slot, and Compact Radiative Divertor divertors into a compact design that is compatible with high-elongation and high-triangularity double-null configurations. This design offers three key advantages. First, its compact structure, with the X-point positioned near the dome top, reduces the divertor volume while increasing the overall plasma volume. This configuration effectively traps impurities away from the X-point, thereby reducing the risk of impurity transport into the core plasma and enhancing particle control. Second, the optimized strike-point location on the horizontal target plate, close to the private flux region’s pumping slot, promotes neutral trapping in the XSC divertor, thereby enhancing XSC energy dissipation. Third, the XSC divertor integrates a large-angle V-shaped geometry with the common scrape-off layer plasma, expanding the radiation loss zone. These features position the XSC divertor as a promising solution for addressing the challenges of heat and particle exhaust in future fusion reactors.