The phenomenon of multifaceted asymmetric radiation from the edge with new graphite limiters in Hefei Tokamak-7

Abstract

A new set of actively cooled toroidal double-ring graphite limiters have been developed in Hefei Tokamak-7 (HT-7) for long-pulse operation. In this paper, the phenomenon of multifaceted asymmetric radiation from the edge (MARFE) has been studied in the ohmic discharges in HT-7. The best correlation has been found between the total input ohmic power and the product of the edge line-averaged density and Z eff. The critical density of the MARFE onset is observed in the region of , where f GW=n¯e/n GW (here n¯e is the maximum line-averaged electron density and n GW is the Greenwald density).