2.1: Experiments with the European 2 MW coaxial-cavity pre-prototype gyrotron for ITER

A 2 MW, CW, 170 GHz coaxial-cavity gyrotron for electron cyclotron heating and current drive in the International Thermonuclear Experimental Reactor (ITER) is under development within an European Gyrotron Consortium (EGYC*). To support the development of the industrial prototype of a CW gyrotron, a short pulse tube (pre-prototype) is used at KIT (former FZK) for experimental verification of the design of critical components, as electron gun, beam tunnel, cavity and quasi-optical (q.o.) RF-output coupler. Significant progress was achieved recently. In particular, RF output power of up to 2.2 MW with 30 % output efficiency has been obtained in single-mode operation at 170 GHz. Furthermore, an excellent quality of the RF output beam with ~96 % Gaussian mode content has been obtained by using a new quasi-optical RF output system.