Simulation of Wall Erosion–Deposition Evolution under Boronized Wall Conditions in EAST

A multi-physics simulation framework coupling SDTrim.SP and DIVIMP is developed to investigate the erosion–deposition evolution of wall materials under plasma exposure following boronization in the EAST tokamak. The model assumes amorphous target materials and employs background plasma profiles constrained by EAST probe diagnostics together with OSM–EIRENE–DIVIMP (OEDGE) calculations. This framework enables quantitative simulations of material erosion, migration and deposition on the boronized tungsten wall. A pure boron (B) coating and a mixed C–B–O–W layer surface are considered in the simulations. The results show that, with sustained plasma–surface interactions, material erosion and impurity transport gradually evolve towards a steady state, and different erosion–deposition properties have been found for different regions. In the outer divertor region with high electron temperature and incident particle flux, erosion of both B coating and tungsten substrate dominates, accompanied by local redeposition driven by tungsten and low-Z impurities. Redeposition of eroded tungsten remains at the divertor vicinity. In contrast, net deposition on the first wall is mainly driven by light impurities, where the B flux originates from global transport of B eroded from the divertor coating. The local net erosion and deposition pattern in each region are determined by local plasma conditions. This study can provide theoretical insights for wall-conditioning and impurity transport control in tokamaks.