To the theory of high-power gyrotrons with uptapered resonators

Journal Article · Sat May 15 00:00:00 EDT 2010 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.3425876· OSTI ID:21371142

Dumbrajs, O ^[1]; Nusinovich, G S ^[2]

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1. Institute of Solid State Physics, University of Latvia, Kengaraga Street 8, Riga LV-1063 (Latvia)
2. Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, Maryland 20742-3511 (United States)

In high-power gyrotrons it is desirable to combine an optimal resonator length with the optimal value of the resonator quality factor. In resonators with the constant radius of the central part, the possibilities of this combination are limited because the quality factor of the resonator sharply increases with its length. Therefore the attempts to increase the length for maximizing the efficiency leads to such increase in the quality factor which makes the optimal current too small. Resonators with slightly uptapered profiles offer more flexibility in this regard. In such resonators, one can separate optimization of the interaction length from optimization of the quality factor because the quality factor determined by diffractive losses can be reduced by increasing the angle of uptapering. In the present paper, these issues are analyzed by studying as a typical high-power 17 GHz gyrotron which is currently under development in Europe for ITER (http://en.wikipedia.org/wiki/ITER). The effect of a slight uptapering of the resonator wall on the efficiency enhancement and the purity of the radiation spectrum in the process of the gyrotron start-up and power modulation are studied. Results show that optimal modification of the shape of a slightly uptapered resonator may result in increasing the gyrotron power from 1052 to 1360 kW.

• OSTI ID: 21371142
• Journal Information: Physics of Plasmas, Vol. 17, Issue 5; Other Information: DOI: 10.1063/1.3425876; (c) 2010 American Institute of Physics; ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
HIGH-FREQUENCY HEATING
ITER TOKAMAK
MICROWAVE AMPLIFIERS
QUALITY FACTOR
RESONATORS
AMPLIFIERS
CLOSED PLASMA DEVICES
DIMENSIONLESS NUMBERS
ELECTRONIC EQUIPMENT
EQUIPMENT
HEATING
MICROWAVE EQUIPMENT
PLASMA HEATING
THERMONUCLEAR DEVICES
THERMONUCLEAR REACTORS
TOKAMAK DEVICES
TOKAMAK TYPE REACTORS