Dynamical stability of plasma irregularities produced by powerful radio wave in the F region of the ionosphere

The paper demonstrates that the artificial plasma irregularities in the F region of the ionosphere are dynamical structures caused by the component of temperature gradient parallel with gravitational field. The concept is justified by theoretical estimates of critical parameters of thermal convection in the heated ionospheric volume. Presented results of radar observations of small-scale irregularities are explained by the thermal convection.