Ionization irregularities in the E region during counter electrojet

Abstract

A Langmuir probe, designed for studying the D and E region electron density and its irregularities, was flown on a Centaure rocket from Thumba, India (dip 0 deg 47 min S), during a strong counter electrojet on August 17, 1972 at 1532 local time. A sharp layer of ionization was detected at a height of 94 km. Wave-like perturbations in electron density, which do not resemble the irregularities generated through the cross field instability, were observed around 93 km. Irregularities due to the crossfield instability were observed in the region of negative density gradients above 94 km. These observations support the conclusion that the electric fields are reversed in the counter electrojet. Irregularities in 1-15 m scale sizes were observed in the 106-112 km region with amplitudes of 1-2% of the ambient density. The nature of these irregularities is similar to those generated through electron streaming as observed in earlier flights during strong and normal electrojet periods.