Status of the 1-MW, 140-GHz, CW Series-Gyrotrons for W7-X

Dammertz G., Alberti S., Arnold A., Erckmann V., Gantenbein G., Giguet E., Heidinger R., Hogge J.P., Illy S., Kasparek W., Koppenburg K., Laqua H., Legrand F., Leonhardt W., Liévin C., Michel G., Neffe G., Piosczyk B., Schmid M., Thumm M., Tran M.Q.:

Abstract: The first series gyrotron for the Stellarator W7-X at Greifswald delivered a power of 920 kW at an efficiency of 45% (with energy recovery) at a pulse length of 180 s. 30 minute pulses were performed with the same output power at slightly reduced efficiency.

The second series tube delivered 1 MW with a pulse length of 1 ms and about 800 kW for 3 ms. For the longer pulse the accelerating voltage had to be reduced in order to avoid mode hopping. The results will be reported.