On the continuity equation for electron density in the ionosphere

Abstract

The continuity equation for electron density is discussed by considering some representative chemical reactions in the ionospheric regions. Without neglecting the time-dependent and the transport terms, the equation is modified so that the decay term has a form of L = λ [X 2] N e + λ α [X 2] , where α and λ are the rate coefficients of dissociative recombination and ion-atom interchange reactions, respectively, and the remaining terms are formulated. It is found by rather rough test that these remaining terms are small, and the continuity equation with the decay term of /tl-type function, which is usually used for the discussion of steady state, may be used for the non-steady state cases without serious errors. In some cases, however, these remaining terms may be appreciable, and their effects on the continuity equation for electron density may not be neglected. Finally, some detailed formulations for equilibrium electron density are given.