AbstractFor the future stellarator W7-X of IPP at Greifswald, a powerful electron cyclotron resonance heating facility is being built which will include 10 gyrotrons at 140 GHz with a CW power of 1 MW each plus two optional gyrotrons at 70 GHz. The millimetre wave power will be transmitted fully optically via two multiple-beam wave guides (MBWG) with a length of about 50 m. This paper presents calculations and low-power measurements of the transmission characteristics of a prototype MBWG, which promises a high transmission efficiency for the ECRH system under construction. Furthermore, tests of prototype water-cooled mirrors are discussed.
Development of high power gyrotrons for advanced fusion devices