Simulation of divertor heat flux widths on EAST by BOUT++ transport code*

The BOUT++ edge plasma transport code is applied to study the effects of drifts and neutral on the divertor heat flux widths of EAST steady state H-mode discharges. The heat flux widths from the simulations are in reasonable agreement with the experiments, however, the widths from both the simulations and experiments turn out to be a factor of 2 larger than Goldston’s drift-based model and Eich’s multi-machine scaling, which may probably be due to the dominant RF heating on the EAST discharges involved in this work. Drifts are found to have dramatically increased both the heat flux and its width. Neutral seems to have increased the density and temperature gradient at the divertor region, which makes the heat flux increased by a factor of about 4.4 while the heat flux width decreased by about 26%. Detailed analysis about the effects of drifts and neutral will be presented. Further simulation on EAST NB heated H-mode discharges will be carried out and included in this work to figure out the heating scheme effects on divertor heat flux width.