Response of the Equatorial Ionosphere to the Annular Solar Eclipse of 15 January 2010
Lijo Jose, C. Vineeth, Tarun Kumar Pant, Karanam Kishore Kumar
Abstract
Abstract This paper presents the response of the equatorial ionosphere to the noon time annular solar eclipse of 15 January 2010. The observation has been made using a Digisonde, Meteor Wind Radar, and Proton Precession Magnetometer over Trivandrum, (8.5 o E; 77 o N; dip lat 0.5 o N), a geomagnetic dip equatorial station in India. It has been found that the E , F 1 , and F 2 regions of the equatorial ionosphere respond to solar eclipse with different time delays, F 1 being responding faster and the E and F 2 regions slower. Though there have been studies on the delayed response of F 2 region during the solar eclipses, the delayed response of E region is quite unexpected since this region is dominated by the recombination chemistry. The plausible reasons for this have been explored, and it is suggested that the downward diffusion of atomic oxygen plays a major role for the observed phenomenon.