Theoretical study on mode competition between fundamental and second harmonic modes in a 0.42 THz gyrotron with gradually tapered complex cavity

Journal Article · Thu Oct 15 04:00:00 EDT 2015 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.4933410· OSTI ID:22486459

Zhao, Qixiang; Yu, Sheng; Zhang, Tianzhong ^[1]; Li, Xiang ^[2]

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1. Terahertz Science and Technology Research Center, University of Electronic Science and Technology of China, Chengdu 610054 (China)
2. Queen Mary University of London, London E1 4NS (United Kingdom)

In this paper, the nonlinear dynamics of mode competition in the complex cavity gyrotron are studied by using multi-frequency, time-dependent theory with the cold-cavity longitudinal profile approximation. Based on the theory, a code is written to simulate the mode competition in the gradually tapered complex cavity gyrotron operating at second harmonic oscillation. The simulations tracking seven competition modes show that single mode oscillation of the desired mode TE{sub 17.4} at 150 kW level can be expected with proper choice of operating parameters. Through studying on mode competition, it is proved that the complex cavity has a good capability for suppressing the mode competition. Meanwhile, it is found that TE{sub 17.3} could be excited in the first cavity as a competition mode when the gyrotron operating at large beam current, which leads to that TE{sub 17.3} and TE{sub 17.4} with different frequencies can coexist stably in the complex cavity gyrotron with very close amplitudes. Thus, the complex cavity might be used for multi-frequency output gyrotron.

• OSTI ID: 22486459
• Journal Information: Physics of Plasmas, Journal Name: Physics of Plasmas Journal Issue: 10 Vol. 22; ISSN PHPAEN; ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
AMPLITUDES
BEAM CURRENTS
CAVITY RESONATORS
COMPUTERIZED SIMULATION
HARMONICS
MICROWAVE AMPLIFIERS
OSCILLATION MODES
THZ RANGE
TIME DEPENDENCE