P.F. Denisenko - Dr. Sc. (Phys.-Math.), Professor, Department of Radiophysics and Space Research, Research Institute of Physics SFU (Rostov-on-Don). E-mail: denis@sfedu.ru A.I. Skazik - Ph. D. (Phys.-Math.), Associate Professor, Senior Research Scientist, Research Institute of Physics SFU (Rostov-on-Don) G.A. Zbankov - Ph. D. (Phys.-Math.), Senior Research Scientist, Research Institute of Physics SFU (Rostov-on-Don)