Evolution of low frequency electromagnetic fluctuations in low- and middle-latitude ionosphere

The electromagnetic equations of qyrotropic waves in the general form have been examined. The analysis shows that attenuation of one of modes tends to zero in the perpendicular direction to the magnetic field while along this direction the attenuation is finite. Basing on this feature it was supposed that low frequency electromagnetic fluctuations tend to expand along the magnetic field. It forms in the ionosphere long areas with invariable direction of the electric field and current and weakly variable magnitude of these parameters. This assumption was checked by numerical solving of the direct problem of electromagnetic fluctuation evolution.