Status of the 1 MW, CW gyrotrons for the stellarator W7-X

Experiments were performed with the 1 MW, CW 140 GHz prototype gyrotron for the stellarator W7-X. The maximum output power of 970 kW at an efficiency of 44% was achieved for a pulse length of 11.7 s. For 180 s, an output power of 890 kW could be obtained. At reduced output power of 540 kW, a pulse length of 939 s was achieved. The second prototype has been improved in order to achieve the specified values. Experiments can be performed.