STUDY OF DIVERTOR HEAT-FLUX IN AUXILIARY HEATED DISCHARGES IN JT-60

The behaviour of the heat flux to the JT-60 divertor are investigated in the lower hybrid range of frequency (LHRF) heated and neutral beam heated discharges from the view point of the plasma wall interaction by using an IRTV camera. It is found that the power balance is determined by the distance between the launcher and the separatrix of the plasma with LHRF heating. As the LHRF power increases, the peakedness of the heat flux increases. The parameter dependence of the peaking ratio is investigated for neutral beam heated discharges. It is found that the peaking ratio is a function of the divertor geometry. This behaviour is explained by a simple model that takes into account the response of the divertor plasma to the transport of the heat flux and particle flux.