Reconstruction of altitude profiles of electron collision effective frequency in isotropic flat-layered ionosphere

An inverse problem of reconstructing the altitude profiles of electron collision effective frequency in the ionosphere has been considered. In geometrical optics approximation, the problem is reduced to an Abel-type integral equation. The equation obtained has been analyzed numerically and an example of reconstruction of $\nu_{{\rm eff}}(z)$ for a parabolic ionospheric layer has been given.