Design of a Closed V-shape Slot X-Divertor to improve divertor detachment and pumping in HL-3 with SOLPS-ITER

To improve detachment and neutral density/pressure in the long-leg open X-Divertor of Huanliu-3 (HL-3), a Closed V-shaped slot X-Divertor (CVXD) is proposed, which integrates an X-Divertor magnetic configuration with a closed V-shaped slot divertor structure. The physical characteristics of the CVXD are analyzed by SOLPS-ITER, with drifts activated. It was found that the CVXD facilitates divertor detachment at a significantly lower threshold density due to its highly efficient retention of both recycling neutrals and impurities, which enables more efficient pumping as well. In addition, the CVXD effectively mitigates the impact of drifts that pushes particles away from the strike point in the open X-Divertor. Furthermore, a detailed scan of the divertor target particle reflection angle suggested that a higher level of the closure enhances those advantageous features of the CVXD. These findings provide valuable insights for the design and optimization of the future divertor upgrade in HL-3, and highlight the significant potential of the CVXD for application in future fusion reactors.