Modelling of carbon erosion and re-deposition for the EAST movable limiter

The movable limiter at the mid-plane of the Experimental Advanced Superconducting Tokamak (EAST) with carbon coatings on the surface was exposed to edge plasma to study the material erosion and re-deposition. After the experiments, the carbon erosion and re-deposition is modelled using the 3D Monte Carlo code ERO. The geometry of the movable limiter, 3D configuration of the plasma parameters and electromagnetic fields under both limiter and divertor configurations have been implemented into the code. In the simulations, the main uncertain parameters such as carbon concentration ρ_c in the background plasma and cross-field transport coefficient D⊥ in the vicinity of surface according to the ‘funneling model’, have been studied in comparison with experiments. The parameter ρc mainly influences the net erosion and deposition profiles of the two sides of the movable limiter, while D⊥ mostly changes the profiles on the top surface.