High-frequency radio-wave propagation through plane-stratified ionospheric models


  • Gary H. Price


The sensitivity of refractive effects to profile shape in the propagation of high-frequency radio waves through the ionosphere is examined for a planar isotropic trapezoidal model of the electron-density variation with height. For a family of trapezoidal profiles with constant peak density, fixed orientation relative to a straight-line path from source to receiver, and constant integrated density along this path, the dependence of the group delay upon profile shape is found to involve only the ratio of the thickness of the peak-density segment of the profile to that of the total profile. For thin profiles, the theory suggests an insensitivity of the group delay to the profile shape for frequencies near the peak plasma frequency divided by the cosine of the zenith angle of the straight-line path, as well as in the familiar high-frequency limit. Expressions for the group delay are also given for parabolic and more general linearly segmented profile models.