Electromagnetic Waves in Parameter Space for Finite Magnetoplasmas

Abstract

High-frequency electromagnetic waves guided by an air-bounded, axially magnetized, plasma column of radius a are studied through the technique of parameter space mapping. The parameter space is 3-dimensional with coordinates ωp/ω, ωb/ω, and c/ωa. In this 3-space, cutoff and resonance loci form surfaces which enclose approximate domains of existence for various classes of waves. Three wave classes, characterized by distinctive cutoff and resonance surfaces, are identified for a magnetized plasma column, and their relation to waves in a boundless plasma, and on a column of small radius (quasistatic waves) is investigated. Also, evidence is found for the continued existence of the surface wave class into the regime ωb>ωp. Parameter space analysis leads to a determination of salient dispersion characteristics for all wave classes and all order of azimuthal variation by a method contributing to physical insight but which avoids exact but laborious numerical computation. Waves are found which change from forward to backward or vice versa with increasing wave number.