Numerical studies of the influence of seeding locations on D-SOL plasmas in EAST

Impurity seeding has been found effective for divertor detachment operations and the seeding location plays a key role in this process. In this work, we use the fluid code SOLPS-ITER to study the influence of seeding locations on divertor and scrape-off layer (D-SOL) plasmas in Experimental Advanced Superconducting Tokamak (EAST) with neon seeding. Simulation results indicate that the neon is a highly effective impurity in mitigating the heat flux and electron temperature peaks on the target of the divertor and achieving the partial detachment on both inner and outer targets. Further, by comparing results of the seeding at the private-flux region (PFR) plate (called ‘XP’ location) and the outer target (called ‘XP’ location), we find that the impurity density and power radiation for TP case are higher in core and upstream regions and lower in the divertor region than that for seeding at the XP, and the difference becomes more and more obvious as the seeding rate increases. It clearly demonstrates that the seeding at the XP location is more appropriate than at the TP location, especially in high seeding rate conditions.