On the origin of medium-period ionospheric waves and their possible modelling: a short review

Abstract

This article introduces the concept of ionospheric waves with periods from about 15 min to about 4 h as one of the acoustic-gravity wave-induced phenomena. The existence of these medium-period ionospheric waves in the various ionospheric layers is supported by the results of a data analysis which has shown remarkable characteristics in occurrence and direction of the waves with a period not longer than about 2 h. The explanation offered is based on the assumption that a unique phenomenon capable to launch acoustic-gravity waves related to such ionospheric waves is the sudden change in physical conditions of the atmosphere due to the passage of the solar terminator.