Stability analysis of a coaxial-waveguide gyrotron traveling-wave amplifier

Journal Article · Sat Oct 01 04:00:00 EDT 2005 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.2083367· OSTI ID:20702268

Hung, C L; Yeh, Y S ^[1]

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1. Department of Communication Engineering, National Penghu University, Penghu, Taiwan (China)

The gyrotron traveling-wave tube (gyro-TWT) amplifier is known to be highly susceptible to spurious oscillations. This study develops a simulation approach to analyze the stability of a coaxial-waveguide gyro-TWT with distributed wall losses. The interplay among the absolute instabilities, the gyrotron backward-wave oscillations, and the circuit parameters is analyzed. Simulation results reveal that the distributed wall losses effectively stabilize spurious oscillations in the coaxial gyro-TWT. Furthermore, the wall resistivity of the center conductor is shown to be an additional effective mechanism for suppressing oscillations. Under stable operation conditions, the coaxial gyro-TWT with distributed losses is predicted to generate 435 kW in the Ka band with 31% efficiency, a saturated gain of 45 dB, and a bandwidth of 1.86 GHz ({approx_equal}5.8%) for a 70 kV, 20 A electron beam with an {alpha}(={nu}{sub perpendicular})/{nu}{sub z})=1.0 and an axial velocity spread of {delta}{nu}{sub z}/{nu}{sub z}=5%.

• OSTI ID: 20702268
• Journal Information: Physics of Plasmas, Journal Name: Physics of Plasmas Journal Issue: 10 Vol. 12; ISSN PHPAEN; ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
MICROWAVE AMPLIFIERS
SIMULATION
STABILITY
TRAVELLING WAVE TUBES
TRAVELLING WAVES
WAVEGUIDES