The amplitude fluctuations of the radio wave scattered from a thick ionospheric layer with weak irregularities

Abstract

The signal received at the ground from a satellite or radio star shows small fluctuations of both phase and amplitude, which are produced by irregularities of refractive index in the ionosphere. The amplitude fluctuations are much the easier to measure and this paper examines theoretically what can be learned about the ionosphere from a study of amplitude fluctuations alone. The departure of the amplitude from its mean value is a function of position on the ground and can be described by a two dimensional autocorrelation function, whose Fourier transform is called the Spectral Intensity function. The paper shows how to find this function, and studies its properties for a thick ionospheric layer with field-aligned irregularities. In many cases it displays a minimum value at a spatial frequency which depends on the mean height of the scattering layer. The value of the function at the minimum depends on the thickness of the layer. © 1965.