STUDY OF POWER LOAD ON TDEV DIVERTOR PLATES WITH AN INFRARED CAMERA

An infrared (IR) camera has been installed on TdeV (Tokamak de Varenne s) to view both the inner and the outer divertor plates. With a finite element code (PDE Protran), the energy deposited on the plates is cal culated from the surface temperature profile measured by the IR camera . The experimental results have revealed that the divertor plate tempe rature decreases with an increase of the main plasma density, suggesti ng that the plasma detaches from the divertor plates at higher plasma densities (above 4.0 x 10(19) m(-3)). During divertor biasing, the hea t flux increases on the plates of the 'active divertor as a result of the E X B flow. However, energy deposition can be reduced by increasin g the plasma density. The neutral gas pressure in the divertor region increases strongly at higher plasma density, and appears to be correla ted with the reduction in deposited energy.