A high-power long-pulse 140-GHz gyrotron oscillator has been designed, constructed, and tested. Key features of the gyrotron include an internal converter to transform the TE28,7,1 operating mode to a Gaussian output beam, a single-stage-depressed collector, and a chemical-vapor-deposition diamond output window. Peak output powers up to 930 kW at 34% efficiency have been demonstrated at 5-ms pulse lengths. Due to power supply limitations, long-pulse operation was not possible for beam currents above 25 A. At 25-A beam current and 500-kW output power, pulse lengths up to 700 s in duration were achieved. The gyrotron has been shipped to the Wendelstein 7-X facility in Greifswald, Germany, where long-pulse demonstrations up to 180s will be carried out at the 930-kW power level.
", the 140-GHz megawatt-class gyrotron developed by Communication and Power Industries (CPI) , and the 170-GHz 1-MW gyrotron (GYCOM, Russia) in long-pulse measurements . One proposed explanation is that thermal heating of the gyrotron cavity results in an increase of the cavity radius and thereby decreases the resonant frequency of the operating mode. "
[Show abstract][Hide abstract] ABSTRACT: A simple approximate theory of background plasma influence on the electromagnetic properties of high-power gyrotron cavities is presented. It is shown that a background plasma slightly reduces the operational frequency of gyrotrons, increases the quality factors of operational and neighbouring modes, and modifies the longitudinal field distribution in the gyrotron cavity. The calculated downshift of the operational frequency is compared with long-pulse measurements performed in 140-GHz 1-MW continuous wave gyrotron experiments at Forschungszentrum Karlsruhe
[Show abstract][Hide abstract] ABSTRACT: Thesis research directed by: Electrical Engineering. Title from t.p. of PDF. Thesis (Ph. D.) -- University of Maryland, College Park, 2005. Includes bibliographical references. Text.
[Show abstract][Hide abstract] ABSTRACT: Vacuum electron devices (VEDs) are the most powerful and efficient sources of coherent radiation throughout the microwave and millimeter wave bands. Traditional applications of powerful VEDs are in such areas as defense, radar, communications, or industrial heating. This presentation will review prospects for new applications in scientific research, especially in large scale applications, sometimes referred to as "Big Science." Opportunities are promising in at least three fields: plasma heating in the program of nuclear fusion energy research; particle acceleration; and terahertz technology
Vacuum Electronics Conference, 2006 held Jointly with 2006 IEEE International Vacuum Electron Sources., IEEE International; 01/2006
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