The book is devoted to the theory of dynamic processes in weakly ionized ionospheric plasma. The focus is on regions E and F, which play an important role in the ionospheric propagation of radio waves. For different altitudes, the influence of the movement of neutral particles on the movement or redistribution of the ionized component is considered. Magnetic hydrodynamics of ionospheric gas . Mechanisms of occurrence of inhomogeneities of electronic concentration and sporadic layers. are analyzed. The problems of excitation in the ionosphere of currents and electrostatic fields . Much attention is paid to the theory of diffusion of ionospheric inhomogeneities.