Large-scale Irregularities In The Equatorial Ionosphere

Abstract

Variations in the Faraday fading period of the 40 MHz signal from satellite BE-B have been used to study large-scale irregularities in the equatorial ionosphere. It is found that the irregularities have sizes ranging from 50–400 km, with an average value of 160 km. The observed amplitudes lie between 0.15 and 3.3 per cent of the background total electron content and the latitude variation of amplitude shows a maximum at the magnetic equator and a minimum at a dip of about 22°S. It is suggested that the irregularities are caused by atmospheric gravity waves with a period of around 40 min. The irregularities occur mainly between 0600–1100 LT.