An investigation of solar flare effects on equatorial ionosphere and thermosphere using co-ordinated measurements

S G Sumod,Tarun Kumar Pant

doi:10.1186/s40623-019-1105-8

Abstract

The response of equatorial ionosphere–thermosphere system to the X3.8 solar flare of January 17, 2005 has been studied using the coordinated measurements of GPS-derived Total Electron Content (TEC), OI 630.0 nm dayglow and magnetic field measurements over a dip equatorial station Trivandrum (8.5° N, 77° E, dip 0.5° N), in India. It has been observed that Equatorial Electrojet (EEJ) as inferred using the ground-based magnetometers and GPS-derived TEC measurements show prompt enhancements during the peak flare, as expected. Interestingly, the temporal evolution of TEC at different latitudes revealed that the X3.8 class flare produced significant weakening of the plasma fountain and hence in the Equatorial Ionization Anomaly (EIA). Furthermore, the response of OI 630.0 nm dayglow during the flare is found to be strongly affected by the prevailing electrodynamics. The plausible physical mechanism for these effects is discussed in context of the current understanding of the neutral and electrodynamical coupling processes.

Highlights

Solar flares are sudden burst of radiations coming from the sun, which significantly alter various physical and chemical processes in the terrestrial upper atmosphere
An attempt is made to investigate the effects of X3.8 solar flare, which occurred on January 17, 2005, over equatorial ionosphere–thermosphere system, using combined high cadence measurements of thermospheric OI 630.0 nm dayglow, GPS-measured ionospheric Total Electron Content (TEC) and the strength of Equatorial Electrojet (EEJ)
Prompt responses have been noticed in the magnetic field inferred EEJ and GPS-measured TEC measurements

Summary

Introduction

Solar flares are sudden burst of radiations coming from the sun, which significantly alter various physical and chemical processes in the terrestrial upper atmosphere. An attempt is made to investigate the effects of X3.8 solar flare, which occurred on January 17, 2005, over equatorial ionosphere–thermosphere system, using combined high cadence measurements of thermospheric OI 630.0 nm dayglow, GPS-measured ionospheric Total Electron Content (TEC) and the strength of Equatorial Electrojet (EEJ).

Results

Conclusion