Development and application of European high power CW gyrotrons for ECRH experiments

In the frame of a collaboration between Association Euratom-CEA, Association Euratom-Confederation Suisse and Thomson Tubes Electroniques, a high power quasi-CW gyrotron number TH 1506 working at the frequency of 118 GHz has been developed for plasma heating and current drive by Electron Cyclotron Resonance (ECR) interaction. The RF output of the gyrotron TH 1506 is under a Gaussian TEM/sub 0,0/ mode through a sapphire window cooled at liquid nitrogen temperature, characterized by a global efficiency of 30% after conversion to the HE11 mode. This mode allows a low losses transmission. Three of these tubes, rated at 500 kW 2 s, will be used for the Tokamak TCV and six tubes, 500 kW 5 s or 400 kW 210 s, for the Tokamak Tore Supra. One prototype and three series tubes have already been manufactured and accepted.