Spectrum of phase fluctuations during probing of ionosphere

The phase fluctuations spectrum of probing radio waves reflected by an ionospheric layer is calculated assuming a layer with a linear profile of the dielectric permittivity, from an earlier established power law scale spectrum of inhomogeneities in the F-layer. For the case of oblique probing first the space spectrum of phase fluctuations is determined as the Fourier transform of the signal correlation function and then the time spectrum is obtained assuming a frozen transport of inhomogeneities at some constant velocity v. The same spectrum is obtained for the two cases of longitudinal drift and transverse drift, when the inhomogeneity scale is much smaller than the layer thickness and much larger than the dissipation scale. The phase fluctuation spectrum was also determined experimentally, from the spectrum of Doppler frequency shifts in a probing signal reflected by the ionosphere (measurements were made at the Moscow State University over the March-October 1979 period). The same procedure applies to theoretical and experimental determination of the phase fluctuation spectrum in the case of vertical probing.