Rocket borne in-situ electron density and neutral wind measurements in the equatorial ionosphere—results from the January 2010 annular solar eclipse campaign from India

Abstract

One of the recent developments in the form of a novel probe for simultaneous in-situ measurements of Electron density and Neutral Wind (ENWi) parameters was extensively made use of during the annular solar eclipse that passed right over the magnetic dip equatorial station, Trivandrum in India. The response of the equatorial ionosphere to the annular solar eclipse of January 2010 is investigated using the data from ENWi and other ground based instruments like digital Ionosonde, HF radar, magnetometer etc. Significant effects on the neutral wind components and electron densities during the peak phase of the eclipse are brought out by the ENWi data. A clear reversal in the zonal neutral wind is observed during the rocket flights at the peak phase of the eclipse as well as in the flight conducted 3 h later. The ground magnetic field measurements revealed the reversal of electrojet during the eclipse alongwith blanketing Es layers vindicating the earlier hypothesis that blanketing Es layers manifest over magnetic equatorial regions only during periods of either weak or reversed electrojet (counter electrojet). The HF radar results independently substantiate the in situ measurements with regard to the location of the irregularities and their Doppler velocities. The regional scale changes that have been brought about by the Solar eclipse both in the neutral and ionized medium and the consequent electrodynamics are highlighted.