Propagation in isotropic plasma waveguides

The paper considers the propagation behaviour of a circular waveguide enclosing either an axial or an annular column of isotropic plasma. The effect of the glass walls of the container required to enclose an actual gaseous plasma is exactly taken into account. The phase-change and attenuation coefficients of both structures are computed for a range of parameters relevant in microwave applications. It is evident that the circularly symmetric mode of the axial column has characteristics suited to devices employing forward waves, whereas the circularly symmetric mode of the annular structure is suited to devices employing the backward wave. A brief review of possible passive- and active-device applications of the structures is presented and some of the limitations on the realisation of these devices noted. An equivalent transverse-network representation for a radially stratified isotropic structure is presented in the Appendix, thereby making possible the computations described in the paper.