Development of a 28 GHz 50kW CW Gyrotron for ECRH application

A 28GHz 50kW gyrotron has been developed for ECRH application in plasma fusion system. The gyrotron employed a triode magnetron injection gun, a cylindrical cavity working under a TE02 mode, a built-in quasi-optical mode converter with ~92% conversion efficiency, and a single-stage depressed collector. In the test, a Gaussian beam of 55 kW for 30 s continuous wave at 28 GHz has been achieved. The corresponding total efficiency is 46%. Now the gyrotron system has been delivered to the customer site and has been applied in the installation experiment.