The magnetoionic theory at hydromagnetic frequencies

Abstract

The characteristics of a plane wave propagating in a two component lossless plasma are studied using the approach of the magnetoionic theory for all directions of propagation with respect to that of the static magnetic field and for frequencies ranging from hydromagnetic to radio frequencies. The propagation ranges of the two modes are obtained by a variant of the well-known CMA diagram and the advantages of this new representation are outlined. In the close neighborhood of the directions parallel and perpendicular to the static magnetic field, the dispersion is found to vary rapidly. The electron gyromagnetic and the plasma resonances as well as the cut-off frequency of the high frequency branch of the ordinary electromagnetic mode show discontinuous variations in the close neighborhood of the direction of the static magnetic field. An interesting result of this investigation is that the so-called ion cyclotron resonance frequency is practically independent of the direction of propagation except in the very close neighborhood of the direction perpendicular to that of the static magnetic field. Frequency and spatial dispersion relations are presented for some typical parameters.