RESEARCH ARTICLE


Detecting a Large-Scale Upper-Atmospheric Plasma Inhomogeneity Using the Method of Multifrequency Radio Sounding in the Decametric Wavelength Range



N.T. Afanasiev1, A.N. Afanasiev*, 2, 3, V.P. Markov1
1 Irkutsk State University, Gagarin boulevard, 20, Irkutsk, 664003, Russia
2 Department of Physics, University of Helsinki, Gustaf Hällströmin katu, 2a, FI-00560, Helsinki, Finland
3 Institute of Solar-Terrestrial Physics SB RAS, Lermontov Street, 126a, Irkutsk, 664033, Russia


© 2011 Afanasievet al.;

open-access license: This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International Public License (CC-BY 4.0), a copy of which is available at: https://creativecommons.org/licenses/by/4.0/legalcode. This license permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

* Address correspondence to this author at the University of Helsinki, Department of Physics, P.O. Box 64, FI-00014, Helsinki, Finland; Tel:+358(0)9-191-50676; Fax: +358(0)9-191-50610; E-mail: alexandr.afanasiev@helsinki.fi


Abstract

We examine the problem of transionospheric sounding with satellite radio signals at frequencies that are close to the edge of the radio transparency frequency range of the ionosphere. We derive asymptotic formulas for the group delay time of the transionospheric radio signal and present an example of how they are implemented if there is a localized large-scale electron density inhomogeneity in the ionosphere. Finally, we suggest techniques for detecting large-scale ionospheric inhomogeneities, which are based on numerical-asymptotic synthesis of disturbed distance-frequency characteristics of decametric signals radiated from a low-orbiting or geostationary satellite.

Keywords: Ionosphere, ionospheric disturbances, transionospheric radio sounding.