Hysteresis in Gyrotrons

O. Dumbrajs,1,2 T. Idehara,1 Y. Iwata,1 S. Mitsudo,1 I. Ogawa,3 B. Piosczyk4


1 Research Center for Development of Far-Infrared Region, Fukui University, Bunkyo 3-9-1,

Fukui 910-8507, Japan.

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

Association Euratom - Tekes, P.O.Box 2200, FIN-02015 HUT, Finland.

3 Cryogenic Laboratory, Faculty of Engineering, Fukui University, Bunkyo 3-9-1, Fukui 910-8507, Japan.

4 Forschungszentrum Karlsruhe, Institut für Hochleistungsimpuls- und Mikrowellentechnik,

Association Euratom – FZK, Hermann –von - Helmholtz-Platz 1, D-76344 Eggenstein - Leopoldshafen, Germany.



A general theoretical plot of hysteresis in the plane has been calculated. Some of the simplest hysteresis effects in specific gyrotrons have been predicted and partially already experimentally observed. More complicated effects can be expected by changing the three gun parameters B, Ua, and Uc simultaneously in various combinations. Understanding hysteresis is important in connection with mode competition, frequency tuning, amplitude modulation, and voltage overshooting.