Solar wind-magnetosphere-ionosphere coupling neutral atmosphere effects on signal propagation

On the basis of a one-dimensional parallel propagation model, this thesis describes the dynamical processes of magnetosphere-ionosphere-thermosphere coupling by a three-fluid approach. Different from the conventional methods, which treat the ionosphere as a thin layer and in a steady state, this thesis starts from Maxwellian equation set and the momentum equations of ions, electrons and neutrals, then after simplification, obtains the dispersion relations for left/right-handed polarized modes. As a result, the neutral wind effects are uncovered, including heavy damping at high frequencies (o > 1Hz) and decrease phase velocity in the low altitudes. Different time scales are acquired that the whistler mode will travel at the electron Alfven speed, while the MHD mode will travel at or below Alfven speed. Different types of wave propagation in the ionosphere are revealed, including strong attenuations for the left-handed mode, long wave propagation in low frequencies and traveling, damping waves with standing waves mixed in high frequencies. The electromagnetic wave energy and its attenuation are calculated and the results provide explanation for the maximum frequency of the observed ULF pulsations.