Ionospheric mid-latitude trough and the abrupt scintillation boundary

Abstract

THE mid-latitude trough^1,2 in electron density and the equatorward limit of small-scale F-region irregularity structure apparent in the scintillation of satellite and radio star signals, the scintillation boundary^3,4, are both features of the transition region between the high and mid-latitude ionospheres. There are broad similarities between the morphology and statistical behaviour of the trough and the irregularity boundary^5–7 and, although the individual behaviour of the scintillation boundary and the mid-latitude trough may be related to particle precipitation patterns or plasmapause movements, there is a definite local time variation in their mean relative latitudinal positions when simultaneous observations of the two phenomena are analysed⁸. We have examined this variation in more detail, using data from simultaneous observations of trough and scintillation boundary positions.