Numerical simulation of backward wave oscillator having nonuniform amplitude slow wave structures

Autor: L.D. Moreland, S. D. Korovin, Igor V. Pegel, H.A.M. Roitman, Edl Schamiloglu, Raymond W. Lemke
Rok vydání: 2005
Předmět:
Zdroj: Proceedings of 1994 IEEE 21st International Conference on Plasma Sciences (ICOPS).
DOI: 10.1109/plasma.1994.589065
Popis: Experiments involving backward wave oscillators having nonuniform amplitude slow wave structures (NBWOs) operating in the x-band frequency range have produced 500 MW of rf power with 20% efficiency. To elucidate the processes occurring in the NBWO, and to ascertain the possible advantage of using a nonuniform amplitude sow wave structure over one that is uniform, the authors have performed a simulation study involving several different tubes, nonuniform and uniform, using the 2.5D electromagnetic particle-in-cell code TWOQUICK. The simulations model experiments performed on the SINUS-6 electron beam accelerator at the University of New Mexico. Results of the simulation study are presented. They show that the slow phase velocity surface wave that interacts with the electron beam coexists with an ordinary waveguide mode, which forms a standing wave in both nonuniform and uniform BWOs. Analysis of BWOs using a single particle phase model that accounts for both fast and slow TM waves shows that it may be possible to increase the output power of these tubes in general by choosing the length of the slow wave structure to simultaneously optimize the coupling of the beam to the slow wave, while forcing a transit time interaction between the standing wave and the electronmore » beam, which pumps beam energy directly into the ordinary waveguide mode. The authors discuss the possible advantages of using a NBWO to accomplish this. In addition, comparisons with SINUS-6 experiments are made.« less
Databáze: OpenAIRE