摘要

The effect of increase of the amount of dissipative absorption and intensity of scintillations of radiation from Discrete Cosmic Sources (DCS) is analyzed, as observed in a polar ionosphere region modified by a powerful HF heater. The investigations have been performed at 38 MHz with the use of a 64-beam imaging riometer located at Alaska in the immediate proximity to the HAARP heater. Results of two special heating campaigns of January and October, 2008 are discussed. The radiations from two most powerful discrete cosmic sources in the Northern sky, namely, Cassiopeia A and Cygnus A, transmitted through the artificially disturbed ionospheric region were used as a probe signal. Specific features shown by scintillations of DCS radiation due to natural and artificial Fresnel scale-size plasma irregularities of the polar ionosphere F-layer are analyzed. Power spectra of the scintillations have been determined and used to recover basic spectral parameters of the irregularities and their motion velocities across the line of sight to the source. The amount of additional absorption of the DCS radiation and the electron temperature increase in the ionospheric D-region due to powerful HF heating have been estimated.