Kinetic Modelling of Divertor Fluxes during ELMs in ITER and Effect of In/Out Divertor Plasma Asymmetries

摘要

Particle and energy fluxes to the plasma facing components (PFCs) during edge localized modes (ELMs) are expected to unacceptably shorten the PFCs lifetime in ITER. In order to understand the consequences of kinetic effects of ELMs to PFCs, PARASOL simulations have been carried. Initial 1-D simulations showed that both the in/out asymmetry of divertor parameters before ELMs as well as the magnitude of the ELM energy loss itself have an influence on the in/out asymmetry of the ELM divertor fluxes with the total energy deposited at the divertor being larger at the hotter/lower recycling divertor. The role of the thermoelectric current ( I _SOL) has been studied with further 1-D simulations in which decreasing I _SOL leads to an increase of the ELM power deposition at the colder/higher recycling divertor but the degree of in/out asymmetry is smaller than in the experiment. PARASOL-2D simulations have been carried out to study the effects of plasma drifts on the asymmetries of ELM energy and particle transport. It shows that for the favourable ? B direction the ELM energy flux is predominantly deposited at the inner divertor while for the unfavourable ? B direction it is at the outer divertor, which is in agreement with experimental findings.