Theory of gyrotrons with coaxial resonators

• Published in: IEEE transactions on electron devices Vol. 41; no. 3; pp. 433 - 438
• Main Authors: Nusinovich, G.S., Read, M.E., Dumbrajs, O., Kreischer, K.E.
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.03.1994; Institute of Electrical and Electronics Engineers
• Subjects: 426000 - Engineering- Components, Electron Devices & Circuits- (1990-); AMPLIFIERS; Applied sciences; Coaxial components; Conductors; Electromagnetic heating; Electron beams; ELECTRONIC EQUIPMENT; Electronic tubes, masers; Electronics; ENERGY LOSSES; ENGINEERING; Exact sciences and technology; Frequency; Gyrotrons; HEATING; Impedance; LOSSES; MICROWAVE AMPLIFIERS; MICROWAVE EQUIPMENT; MODE SELECTION; Numerical simulation; Optical coupling; POWER LOSSES; RESONATORS; TUNING; Voltage; Cut off frequency; Energy loss; Coaxial resonator; Starting; Time curve; Numerical simulation; Gyrotron; Electron tube; Microwave tube; Electrical characteristic
• ISSN: 0018-9383; 1557-9646
• DOI: 10.1109/16.275231

In the development of powerful gyrotrons capable of long-pulse or continuous wave operation the cardinal problem is to provide stable, single-mode highly efficient operation at the desired mode with an acceptable level of ohmic losses in the resonator walls. In the present paper the selective properties of various coaxial resonators as well as ohmic losses of the microwave power in outer and inner conductors are considered. The start-up scenario in powerful gyrotrons is discussed. The results of numerical simulations of a 1 MW, 280-GHz coaxial gyrotron are presented which demonstrate that successive excitation of a number of modes during the voltage rise may not hinder the stable operation of the desired mode on the top of the voltage pulse. An electronic efficiency of 48% is predicted.< >