Modeling and simulation of the erosion damage in tokamak devices during plasma instabilities

Summary form only given. Plasma instabilities such as disruptions, edge-localized modes (ELM), and vertical displacement events (VDE) in tokamaks are the biggest concern for the design and performance of plasma facing component (PFC). These life threatening events are characterized by high-energy dump in short durations, resulting in extremely high temperatures of the PFC that can cause melting, evaporation of the surfaces and eventual contamination of the plasma. Erosion resulting from these processes can be significant and potentially prevent successful operations of the reactor and shorten PFC lifetime.Comprehensive models and simulation efforts are developed and integrated into the well-known and well benchmarked HEIGHTS package using a novel particle-in-cell (PIC) technique in order to characterize the performances of the divertor and reactor walls. The package has several self consistent models that integrate different stages of plasma material interaction during plasma instabilities. Plasma energy deposition, divertor/wall material erosion, and vapor plasma evolution are calculated for the predicted disruption parameters in ITER-like geometry. Photon radiation, its transport and deposition around the divertor area are also calculated. The multi-dimensional models take into account different stages of plasma material interaction and its evolution along time. The extent of the damage depends on the intensity of plasma energy deposited and the time of the deposition since both bulk and surface damages can take place depending on these parameters. For this reason different deposition times for the instability events have been considered ranging from fractions of milliseconds a hundred milliseconds in order to provide comprehensive evolution of material erosion and transport. Simulation results of the integrated modeling show clearly that a single plasma disruption event can cause a significant local damage of the divertor plate, therefore severely limiting the component lifetime. Comparison with other numerical methods and recent experiments are also analyzed and discussed.