Equations for small longitudinal low-frequency potential disturbances in the inhomogeneous ionosphere with account for Coulomb collisions

General equations describing longitudinal small low-frequency potential disturbances in single-ion approximation with regard to heterogeneity of background state of concentrations and of ionosphere plasma component temperatures for arbitrary orientation of magnetic field are obtained. Coulomb collisions between charged particles and collisions of charged particles with neutral ones, as well as, disturbances of concentration and of velocity of neutral particles are taken into account. Problem concerning stability of longitudinal disturbances is considered, as well