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

G. Dammertz^1a, S. Alberti², A. Arnold^1a,3, V. Erckmann⁴, G. Gantenbein^1a, E. Giguet⁶, R. Heidinger^1b, J.P. Hogge², S. Illy^1a, W. Kasparek⁵, H. Laqua⁴, F. Legrand⁶, W. Leonhardt^1a, C. Liévin⁶, G. Michel⁴, G. Neffe^1a, B. Piosczyk^1a, M. Schmid^1a, M. Thumm^1a,3, M.Q. Tran²

¹Forschungszentrum Karlsruhe, Association EURATOM-FZK,
^aInstitut für Hochleistungsimpuls- und Mikrowellentechnik, ^bInstitut für Materialforschung I,
Postfach 3640, D-76021 Karlsruhe, Germany,

²Centre de Recherche en Physique des Plasmas, Association Euratom-Confédération Suisse, EPFL Ecublens, CH-1015 Lausanne, Suisse

³Universität Karlsruhe, Institut für Höchstfrequenztechnik und Elektronik,

Kaiserstr. 12, D-76131 Karlsruhe, Germany

⁴Max-Planck-Institut für Plasmaphysik Teilinstitut Greifswald, Association EURATOM,

Wendelsteinstr. 1, D-17491 Greifswald, Germany

⁵Institut für Plasmaforschung, Universität Stuttgart, Pfaffenwaldring 31, D-70569 Stuttgart, Germany

⁶Thales Electron Devices, 2 Rue de Latécoère, F-78141 Vélizy-Villacoublay, France

e-mail: guenter.dammertz@ihm.fzk.de

For the stellarator facility W7-X at Greifswald, Germany, a series of seven gyrotrons with an output power of 1 MW each at 140 GHz in CW operation are being manufactured by European industry. The first series gyrotron delivered an output power of 920 kW at an efficiency of 45 % (with energy recovery) at a pulse length of 180 s. Several pulses with a length of 30 minutes were performed with an output power exceeding 900 kW.

The second series tube delivered 1 MW at a pulse length of 1 ms and about 800 kW for 3 ms. For an increased pulse length, the accelerating voltage had to be reduced in order to avoid mode hopping.

The results of the measurements will be reported.