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Title: Nonstationary oscillation of gyrotron backward wave oscillators with cylindrical interaction structure

The nonstationary oscillation of the gyrotron backward wave oscillator (gyro-BWO) with cylindrical interaction structure was studied utilizing both steady-state analyses and time-dependent simulations. Comparisons of the numerical results reveal that the gyro-BWO becomes nonstationary when the trailing field structure completely forms due to the dephasing energetic electrons. The backward propagation of radiated waves with a lower resonant frequency from the trailing field structure interferes with the main internal feedback loop, thereby inducing the nonstationary oscillation of the gyro-BWO. The nonstationary gyro-BWO exhibits the same spectral pattern of modulated oscillations with a constant frequency separation between the central frequency and sidebands throughout the whole system. The frequency separation is found to be scaled with the square root of the maximum field amplitude, thus further demonstrating that the nonstationary oscillation of the gyro-BWO is associated with the beam-wave resonance detuning.
Authors:
 [1] ;  [2] ;  [3]
  1. Department of Physics, National Central University, Jhongli 32001, Taiwan (China)
  2. Department of Physics and Astronomy, University of California, Irvine, CA 92697 (United States)
  3. (China)
Publication Date:
OSTI Identifier:
22218363
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 20; Journal Issue: 12; Other Information: (c) 2013 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; COMPARATIVE EVALUATIONS; COMPUTERIZED SIMULATION; CYLINDRICAL CONFIGURATION; ELECTROMAGNETIC RADIATION; FEEDBACK; MICROWAVE AMPLIFIERS; OSCILLATIONS; OSCILLATORS; RESONANCE; TAIL ELECTRONS; TIME DEPENDENCE