The heat flux control of the divertor plate via strike-point splitting generated by biased targets was proposed in the HL-2A tokamak (Cui et al 2021 Fusion Eng. Des.173 112963). To understand the helical scrape-off layer (SOL) currents driven by hybrid biasing, two SOL current models (model A and B) are employed. Model A is a simplified 2D model that focuses on investigating the effect of biasing on the sheath and elucidating the fundamental physical mechanism of bias-driven SOL current paths. The potential, charge density, electric field and current densities are calculated. Model B takes into account the actual tokamak geometry and computes the resonant magnetic perturbations (RMPs) generated by bias-driven linear decay currents. Additionally, strike-point splitting is observed in the HL-2A tokamak, indicating that the SOL currents generated by hybrid biasing are capable of generating strong RMPs and consequently influence the magnetic topology. These results confirm the potential of heat/particle flux control by hybrid divertor biased targets.
This paper investigates the use of biased targets in tokamak divertors to control the heat flux on the divertor plate. The study uses 2D particle-in-cell (PIC) models to analyze the helical scrape-off layer (SOL) currents generated by the biased targets. The results show that these SOL currents can influence the magnetic topology and lead to strike-point splitting, which can help in controlling the heat and particle fluxes.