Excitation and propagation of electromagnetic waves in nonuniform density ducts

Abstract

With the use of a full wave formulation, a study is made of radiation and propagation of electromagnetic waves in nonuniform cylindrical ducts excited by given azimuthally symmetric sources. For an infinitely long duct, the eigenfunction set involving both localized and non-localized waves is obtained for arbitrary values of driving frequency, external magnetic-field strength, plasma density, and its variation transverse to the duct axis. Using this set, the radiation characteristics of an annular current immersed in the duct are found for the whistler range. The subsequent propagation of excited waves is then analyzed in a duct whose parameters vary slowly along the external magnetic field. The applications of the results obtained are discussed.