Reduction of divertor plate heat load in Doublet III

The surface temperature of a divertor plate during discharges in the Doublet III tokamak is measured by an infrared scanning camera with a time resolution of 60 ms. The maximum rise in surface temperature during a discharge is around 1200C in a discharge with a mean electron density of 1.5x1013 cm-3 and a plasma current of 360 kA. The e-folding width of the temperature rise profile is approximately 4 cm. By increasing the electron density of the main plasma, the temperature rise of the divertor plate is decreased and the vertical temperature rise profile is broadened. The radiation loss in the divertor region plays an important role in the decrease in power transferred to the divertor plate. (author)