ИСТИНА

We present the results of multi-station ground-based observations of low-frequency electromagnetic fields from the ionospheric source initiated by powerful high frequency (HF) radio-waves emitted by EISCAT/heating facility in the heating experiment carried out by AARI in October 2016.  The components of the ELF/VLF electromagnetic field have been recorded by high-latitude stations, namely “Lovozero”, “Verkhnetulomsky” and “Lotta” at the Kola peninsula and also at the “Barentsburg” station located in Svalbard, Norway. It is shown that at the frequencies close to the first transverse resonance frequency of the Earth‐ionosphere waveguide under same geomagnetic conditions the amplitude of the horizontal magnetic field at the Barentsburg station (946 km to the North from the EISCAT/heating facility) often exceeds the amplitude of the magnetic field at the Lotta station (395 km to the East). But, with all conditions being similar, at the frequencies, higher and less than the first transverse resonance frequency was no such effect. To explain the observed effect the numerical model of the electromagnetic ELF/VLF wave generation and propagation in the Earth-ionosphere waveguide was developed. Using this model, the conditions that may induce an enhancement of the ELF/VLF field at the Barentsburg station relative to the Lotta station are considered.