On conditions of initiation of electric discharges in the middle atmosphere

Abstract

This work is devoted to a study of the conditions of initiation of two types of high-altitude discharges: sprites and halos. A quasi-electrostatic model of generation of the electric field in the middle atmosphere is developed; it takes into account the specific features of charge distribution and charge dynamics in the thundercloud, as well as real profile of the atmospheric conductivity. We take into consideration the nonlinear effects associated with the heating of electrons in the electric field. It is shown that the region where the electric field of the lightning flash exceeds the breakdown field is concentrated around an altitude of about 75 km, which is in agreement with the sprite observations. It is found that the dynamics of the current and discharge of the lightning flash plays a significant role in the initiation of high-altitude discharges in the atmosphere.