Recent Development Of A 1.5 Mw, 140 Ghz Continuous-Wave Gyrotron For The Upgraded Ecrh System At W7-X

To increase the total injected Electron Cyclotron Resonance Heating (ECRH) power in the plasma of the nuclear fusion experiment Wendelstein 7-X (W7-X), an upgrade of the existing gyrotron installation is in progress. The existing ECRH system, currently equipped with ten one-MW-class, 140 GHz continuous wave (CW) gyrotrons, will be augmented by enhanced 1.5 MW tubes, which are based on the successful existing 1 MW gyrotron design.