Diffraction of ATS-6 signals by isolated ionospheric irregularities—Some new aspects

A new model of a Gaussian ionospheric irregularity with perturbation is studied. Analysis of two events of diffraction of ATS-6 radio signals on 40, 140 and 360 MHz by isolated ionospheric irregularities indicates that while one class of events is well described in terms of diffraction by a Gaussian irregularity, the other class of events necessitates the assumption of a more complex irregularity structure. General characteristics of diffraction patterns due to a minor Gaussian perturbation within a larger irregularity are discussed, and an attempt has been made to deduce the structure of the second observed irregularity on the basis of these characteristics. The result suggests the possibility of a distorted double-humped electron density distribution in the irregularity.