VLF wave propagation with an inhomogeneous, anistropic ionosphere

A model of electromagnetic long wave (VLF) transmission with a highly dependent, anisotropic ionosphere is described. The propagation of VLF waves follows the Earth ionosphere conducting medium in the form of self oscillations. The characteristics of these waveguide modes are defined by the electrical and magnetic properties of the wave conductor boundaries and by the frequency band. Inhomogeneity in the ionosphere is taken into account as a continously varying, N layer slab. The differential equations are solved for several profiles of electron density and collision distribution. The model shows reflection and absorption behavior of a magnetoplasma, besides frequency dependent characteristics of damping and relative phase velocity for a realistic ionosphere. Numerical simulations were run for different VLF transmitter phases and amplitudes, then compared with measured data. Diurnal and seasonal variations in the characteristic propagation parameters show good agreement.