Design Considerations of Powerful Second-Cyclotron Harmonic
Coaxial-Cavity Gyrotrons

 

 

C. T. Iatrou(1,3), C. Avramidis(1), J. L. Vomvoridis(1) and B. Piosczyk(2)

(1)National Technical University of Athens, Dept of Electrical and Computer Science Engineering, Division of Electroscience, 9 Iroon Polytechniou St., Athens, Greece

(2)Forschungszentrum Karlsruhe, Association EURATOM-FZK,
Institut für Hochleistungsimpuls- und Mikrowellentechnik (IHM),P.O. Box 3640,
D-76021 Karlsruhe, Germany

(3)permanent address: THOMSON-CSF Services Electroniques Hellas S.A.

2-4 Messoghion Ave., 115 27 Athens, Greece

 

 

 

The paper presents the design considerations of powerful second-cyclotron harmonic coaxial-cavity CW gyrotrons. The introduction of a corrugated inner conductor to a cylindrical gyrotron cavity can result in a selective increase (decrease) of the diffractive-Q of second (first) cyclotron-harmonic modes. In this way, second-cyclotron harmonic modes are able to survive the strong competing action of modes interacting with the beam at the fundamental cyclotron frequency, enabling second-harmonic operation in high-order modes, where the spectrum is very dense. Details are given on the limitations imposed by physical (competition, order of mode) and technological (cooling, manufacturing) limitations on output power and frequency. Simulation results of a preliminary design of a CW second-harmonic coaxial gyrotron delivering at 340GHz output power of the order of 100kW with 20% efficiency are presented, using a time-dependent multi-mode, multi-harmonic, fixed-field code.

 

 

als Vortrag:

26th International Conf. on Infrared and Millimeter Waves, Sept. 10-14, 2001,

Toulouse, France