Effect of gravity on formation conditions of certain instabilities in the ionospheric F region

We consider the behavior of sinusoidal plasma instabilities in the ionospheric F region. An analysis is performed taking account of the contribution of gravity, under conditions of possible formation of instabilities which are associated with the inhomogeneous nature of the plasma motion. Instability is due to plasma inhomogeneity convergence in the presence of the geomagnetic field. The behavior of inhomogeneities of various scales is determined at different times.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 21, No. 11, pp. 1572–1581, November, 1978.