Progress in the development of advanced high power gyrotrons

B. Piosczyk, A. Arnold+, E. Borie, G. Dammertz, O. Drumm+, O. Dumbrajs++ , S. Illy, M. Kuntze,

K. Koppenburg+, M. Schmid and M. Thumm+

Forschungszentrum Karlsruhe, Association EURATOM-FZK, Institut für Hochleistungsimpuls- und

Mikrowellentechnik (IHM), D-76021 Karlsruhe

+ also Universität Karlsruhe, Institut für Höchstfrequenztechnik und Elektronik

++Department of Engineering Physics and Mathematics, Helsinki University of Technology,

FIN-02150 Espoo, Finland.





The work on advanced gyrotrons consists of: (1) the development of a coaxial cavity gyrotrons capable of delivering 2 MW, continuous wave (CW) at 170 GHz, (2) the demonstration of fast frequency step tuning and (3) the work on a slowly tunable multi frequency gyrotron. In the case of the coaxial gyrotron a proof of principle has been demonstrated at pulses around 1 ms and specific problems related to the coaxial system have already been partly investigated. The design of critical components for a CW tube is underway. Fast frequency tuning has been performed by a stepwise frequency variation up to about 15 GHz within 1 s around a central frequency of 140 GHz at a power level of about 1 MW. As a first step towards application a slowly tunable multi frequency 1 MW gyrotron operated between 110 and 140 GHz is under development for application at ASDEX-Upgrade in Garching.