Cyclotron harmonic emission in a Penning discharge

Electrical Engineering, Cyclotron harmonic, emission, Penning discharge

Wilgen, John B. ; Gould, Roy Walter

University:California Institute of Technology

Department:Engineering and Applied Science

关键词: Electrical Engineering, Cyclotron harmonic, emission, Penning discharge;   

Others  :  https://thesis.library.caltech.edu/8596/1/Wilgen-jb-1975.pdf

美国|英语

来源: Caltech THESIS

【 摘 要 】

Microwave noise emission at the harmonics of the electron cyclotron frequency from the magnetized plasma column of a Penning discharge is investigated experimentally. The harmonic emission spectrum is observed using oxygen gas in a variety of discharge configurations. It is found that grid stabilization of the plasmacolumn has very little effect on the emission spectrum. Measurements of the shape and location of the harmonic emission lines are described in detail. On the basis of a microwave interferometer measurement of the electron density, it is concluded that the existence of a hybrid layer somewhere on the plasma column is a necessary condition for the observation of harmonic emission. Therelaxation time and the cathode voltage dependence of the harmonic emission are investigated using a pulse modulation technique. It is found that the emission intensity increases rapidly with the magnitude of the cathode voltage and that the relaxation time decreases with increasing neutral gas pressure. High intensity nonharmonic radiation is observed and identified as resulting from a beam-plasma waveinstability thereby eliminating the same instability as a possible source of the harmonic emission. It is found that the collective experimental results are in reasonable agreement with the single particle electrostatic radiation theory of Canobbio and Croci.