Features of the gyrotropic wave propagation in the homogeneous ionosphere

The quasi-stationary Maxwell equations of the gyrotropic waves have been examined. In contrast to the approach used in the other papers [1]-[3] the general form of the electromagnetic equation of the gyrotropic waves has been considered. The dispersion equation analysis shows that attenuation of one of the mode tends to zero in the perpendicular to the magnetic field direction while along this direction the attenuation is finite (Fig. 1). Basing on this feature we can suppose 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. To check this conclusion the direct problem of the evolution of an electromagnetic fluctuation has been solved numerically. The results show that spherically symmetric fluctuation expands along the magnetic field lines by 5-30 times while in some cases the widening is fully absent (Fig. 2).