Features of propagation of HF signals on mid-latitude paths under conditions of geomagnetic disturbances

Abstract

We present the results of experimental studies of the features of HF-signal propagation on oblique-sounding paths in the Eurasian longitude sector between England and Magadan during geomagnetic disturbances. The joint analysis of the satellite data and the data of vertical and oblique sounding of the ionosphere shows that the appearance of additional signals during magnetic disturbances can be stipulated by refraction of radio waves in the region of the auroral oval and the main ionospheric trough as well as by scattering from small-scale magnetic-field-aligned irregularities near the equatorial boundary of the auroral oval. Based on calculations and comparison with experimental data of oblique sounding of the mid-latitude ionosphere, we identify the “lateral” spreading signals registered on the Magadan — Irkutsk and Inskip (England) — Rostov-on-Don paths as signals scattered by small-scale field-aligned irregularities whose location coincides with the southern boundary of the auroral oval. We show that the Russian and global chirp-ionosonde networks are promising for studying the dynamics of the main ionospheric trough and the auroral oval during geomagnetic disturbances as a manifestation of space weather in the near-Earth environment.