Modeling of tungsten divertor target erosion induced by impurity during edge-localized modes by using a kinetic model

Abstract

The burst of edge-localized modes (ELMs) leads to an increase in the energy and particle fluxes to the divertor target. Tungsten (W) is chosen as the primary candidate material for plasma-facing components (PFCs) in the future fusion devices, and EAST has already upgraded all divertors to use W. Therefore, understanding tungsten target erosion during ELMs and finding the correlation between erosion rate and key ELM parameters are crucial for steady-state operation. In this work, based on the Vlasov–Poisson model (VPM), we develop a one-dimensional kinetic parallel transport code to investigate the parallel transport of particles in the EAST device during ELMs and the resulting target erosion. The EAST experiment (#102182) is simulated by VPM code. The simulation results are compared with experimental data as well as free-stream model (FSM) calculation, showing the accuracy of the code. Considering the presence of lithium (Li) impurities in EAST discharge, the erosion of the W target is simulated. The results indicate that during the burst of ELM, the total average tungsten erosion rate, ${\Gamma }_{\text{total}}^{\mathrm{AVG}}$, is determined by both deuterium (D) and Li ions. D ions dominate the erosion when the ELM frequency (f_ELM) is low (ranging from 50 to 175 Hz), while Li impurities become more important than D⁺ in high-frequency ELMs (f_ELM > 175 Hz). As f_ELM increases, the time-averaged erosion of the W target first increases and then decreases. Therefore, the reduction of W erosion benefits from high-frequency ELMs, with impurity ions being the primary contributor to the erosion.