Observation of Ionospheric Scintillations of Discrete Cosmic Sources with the Use of an Imaging Riometer

Abstract

The effects of scintillations have been investigated theoretically and experimentally for the radiation from discrete cosmic sources scattered from natural and artificial inhomogeneities of the polar ionosphere. The observations were performed with the use of a multibeam phased antenna array of the Poker Flat imaging riometer (Alaska, USA). For quiet ionospheric conditions and weak scintillations the spatial spectrum and transverse motion velocities of the Fresnel inhomogeneities have been recovered. A possibility has been shown theoretically to estimate the time coherence interval of the radiation at the observation point in the case of saturated scintillations and strong turbulization of the polar ionosphere. Examples are analyzed of discrete cosmic sources scintillations owing to artificial ionospheric irregularities induced by a powerful heating facility. The effect of aspect sensitive scattering of discrete cosmic sources radiation by artificial field-aligned, small-scale irregularities has been predicted and detected. Prospects of routine observations of the effects of scintillations and aspect sensitive scattering are discussed for special operation modes heating facility.