Observation and Study of Low-Frequency Oscillations in a 1.5-MW 110-GHz Gyrotron
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Cerfon-2009-Observation and Stud.pdf
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Author(s)
Cerfon, Antoine J.
Choi, Eunmi
Marchewka, Chad D.
Mastovsky, Ivan
Shapiro, Michael
Sirigiri, Jagadishwar R.
Temkin, Richard J.
Date Issued
June 2009
Journal
IEEE Transactions on Plasma Science
Publisher
Institute of Electrical and Electronics Engineers
Citation
Cerfon, A.J. et al. “Observation and Study of Low-Frequency Oscillations in a 1.5-MW 110-GHz Gyrotron.” Plasma Science, IEEE Transactions on 37.7 (2009): 1219-1224. © 2009 Institute of Electrical and Electronics Engineers
Version
Final published version
Abstract
We report the observation of low-frequency oscillations (LFOs) in the range 165-180 MHz in a 1.5-MW 110-GHz gyrotron operating in 3-mus pulses. The oscillations have been measured by a capacitive probe located just before the entrance to the cavity. The LFOs are observed only in a narrow region of beam parameter space, at voltages between 45 and 60 kV, where no microwave emission occurs. When the gyrotron operates near 96 kV, with high output power, they are not seen. The variation of the frequency of the oscillations with electron beam voltage and magnetic compression was measured, and the results are reported. Time-domain analysis of the probe signal shows the influence of the beam current and cathode voltage on the time of onset of the oscillations. The amplitude of the time-domain signal indicates that the trapped electron current associated with the LFOs represents a few percent of the total electron current.
Subjects
trapped electrons
low-frequency oscillations (LFOs)
high-power microwave source
gyrotron
fusion
MIT Department
Massachusetts Institute of Technology. Department of Physics
Massachusetts Institute of Technology. Plasma Science and Fusion Center
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Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.
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DOI of Published Version
http://dx.doi.org/10.1109/TPS.2009.2020903
