Impurity seeding and scaling of edge parameters in ITER

ITER divertor and edge modelling with the ITER B2–EIRENE code including neutral–neutral and molecule–ion collisions has led to updated scaling of the helium density and flux and the DT flux with the pumping speed and the divertor neutral pressure. The replacement of carbon by the addition of seeded impurities (neon) strongly modifies the upstream DT density and DT neutral influx at constant detachment state, i.e. divertor neutral pressure and has a smaller influence on the peak divertor power load. The core plasma performance is modelled with the integrated core-pedestal–SOL (ICPS) model implemented in ASTRA; the operating window with seeded impurities is smaller than with DT injection alone.