Measurement and analysis of resonance cone structure from a finite-sized source at the lower hybrid frequency

Experimental and theoretical investigations of wave propagation from a finite-sized source near the lower-hybrid frequency in an inhomogeneous plasma column are described. The wave is excited electrostatically by coaxial half-cylinders. In the present work, measurements of the RF potential show the occurrence of resonance cones along trajectories emanating from the ends of the cylinders as described for the finite source by Bellan and Porkolab. The numerical solution for an oscillating ring charge in a hot plasma has been obtained to determine the effects of electron and ion temperature on the resonance cone structure. Results show a peak in the RF potential along the resonance cones in agreement with experiment. In addition, the numerical results show a short-wavelength, low-amplitude oscillation occurring on the low-density side of the resonance cone.