Formation mechanism of the lower-ionospheric disturbances by the atmosphere electric current over a seismic region

Anomalous sporadic-E layers were observed before the earthquakes. At the same time seismic activity is accompanied by the formation of an external electric current in the lower atmosphere resulting from the emanation of soil gases and transferring charged aerosols. This current is a source of conducting current perturbation in the atmosphere – ionosphere circuit. It is shown that the electric current flowing into the ionosphere from the atmosphere leads to an increase in the E-layer plasma density. The cause of plasma-density enhancement is that the atmospheric electric currents carry positive charged ions upward and the magnetospheric field-aligned electric currents carry electrons downward to the ionosphere. Furthermore, the horizontal electric field of conductive current forms a thin layer of the electron number density by drift of the long-lived metallic ions in the ionosphere. This paper presents the method for calculating the spatial distribution of electron number density perturbations in the bottom ionosphere due to the appearance of external electric current in the near-earth atmosphere. The results can be applied to the interpretation of observation data of the lower-ionospheric perturbations over seismic regions, typhoons and other catastrophes.