Peculiarities of ULF wave characteristics in a multicomponent ionospheric plasma

We have examined the properties of low-frequency electromagnetic waves in multicomponent ionospheric plasma 1–30 Hz band, using magnetoionic theory. Complex permittivity tensor components and refractive indices normal (ordinary extraordinary) were calculated at altitudes from 80 to 750 km. The calculations show that are highly dependent on frequency height. Polarization ordinary extraordinary is elliptical over entire range frequencies investigated. index polarization demonstrated tend magnetohydrodynamic (MHD) values only lower than 1 Hz. group velocity vector an wave not directed along magnetic field, as follows MHD approximation, but it lies inside a cone within ±(5–10) degrees, depending frequency. practically independent angle with geomagnetic field approximation. proposed method for calculating characteristics ionosphere can be used study ULF propagation both natural artificial sources, which arise under action powerful HF radio upper ionosphere.