Modeling of Damage and Lifetime Analysis of Plasma Facing Components During Plasma Instabilities in Tokamaks

Off normal operating conditions resulting from plasma instabilities such as disruptions, edge-localized modes (ELM), and vertical displacement events (VDE) in tokamaks are to be expected with the potential of high energy deposition on plasma facing components (PFC). This high-energy dump in short duration, will result in extremely high temperatures of the PFC leading to melting and evaporation of the surfaces. Erosion resulting from these processes is life-limiting for the PFC as well as potential plasma contamination and degradation of performance. A comprehensive understanding based on the interplay of all physical processes during plasma instabilities on the divertor plate is necessary in order to improve reliability and characterize the performance of this key component. A novel particle-in-cell (PIC) technique has been developed and integrated into the existing HEIGHTS package in order to verify and have another perspective in assessing these problems.

The HEIGHTS multi-dimensional integrated models take into account different stages of the plasma material interaction and its evolution along time. The extent of the damage will essentially depend on the intensity and duration of energy deposited on PFC. Both bulk and surface damages can take place depending on these parameters. For this reason different deposition times have been considered ranging from several microseconds to tens of milliseconds in order to provide comprehensive evolution of material erosion and transport. Comparison of the newly implemented PIC methods with current HEIGHTS existing models are discussed.