Estimations of edge plasma and impurity performance on HL-2M with EMC3-EIRENE modelling

Abstract

Abstract The three-dimensional edge transport code EMC3-EIRENE has been employed to investigate the edge plasma behavior and carbon impurity transport in the HuanLiuqi-2M (HL-2M) tokamak. It is found that the outboard divertor target has a narrower flux deposition width and therefore undergoes more intense peak heat flux than the inboard one. Detailed analyses of carbon impurity have been performed to obtain deeper insights into the mechanisms of edge impurity transport and mitigation of heat loads. As the increment in upstream density, a larger region in the intrinsic friction force dominant regime has been achieved in divertor region, while less impurity ionization source locates in the thermal force dominant region, and hence a better impurity screening has been obtained. The total power loss induced by carbon impurity shows no significant differences as the upstream density increases when it is higher than 1.5 × 1019 m−3, even though the total number of carbon ions in space obviously decreases. Further study on impacts of the impurity source locations has been performed. The carbon impurity eroded from the vertical part of the outboard target is likely to leak out into the upstream, which is attributed to that the region where the intrinsic friction force dominates is thin. On the other hand, the carbon impurity eroded from the inboard target and the horizontal part of the outboard target is under good control due to the wider region in the intrinsic friction force dominant regime.