3D effects of neon injection positions on the toroidally symmetric/asymmetric heat flux distribution on EAST

The heat flux deposition on the divertor targets with neon impurity injection on EAST has been investigated using the three-dimensional (3D) edge transport code EMC3-EIRENE. The impact of different poloidal neon injection positions on heat flux deposition has been studied. It was found that neon impurities injected at the in- and out-board divertors (i.e. strike points) lead to toroidally asymmetric distributions of heat load on the in- and out-board targets, respectively. However, neon gas puffing upstream shows a toroidally symmetric distribution of heat load. The 3D effects of the neon radiation on the heat load have been investigated with the help of a field line tracing technique, which indicates that neon impurities injected near the strike point can radiate more power and result in a lower heat load compared with upstream neon injection. In order to further verify the asymmetric distribution of heat load, two impurity injection locations away from the strike points at the divertor are investigated, which show the symmetric distribution of heat load as with the upstream neon injection