Excitation of Electromagnetic Waves on Plasma Columns by Usinq Partially Filled Plasma Waveguides

Abstract

An analysis for excitation of the lowest order circular symmetric E-mode on columns of isotropic plasma, using a waveguide partially filled with plasma, is presented. Two alternative configurations (possessing circular symmetry) are discussed. In the first case, the excitation aperture is restricted to the cross-section of the plasma column. In the second one, the partially filled waveguide is completely open-ended and the excitation aperture extends outside the plasma region. In both cases the excitation efficiency (defined as the ratio of the power carried by the guided wave to the total power crossing the launching aperture) is evaluated as a function of various parameters and the results are discussed. It is found that, a partially filled guide using an iris (which restricts the excitation aperture to the plasma cross-section) is better suited than an ‘open-ended partially filled waveguide’.