A study on the response of Indian dip and low latitude ionospheric regions to a limb centred X9.0 class solar flare

Abstract

In this paper, we present how Indian dip equatorial and low latitude ionospheric system responded to a limb centred X9.0 class of solar flare event using GPS-TEC, Ionosonde and magnetometer measurements. The limb centred X9.0 solar flare was materialise on 05 December 2006 at the heliography coordinate S07E68 and NOAA 10930 active region, started at 10:18 UT (15:48 IST), peaked at 10:35 UT (16:05 IST), and decayed by 10:45 UT (16:15 IST). The measurements of the total electron content (TEC) of 30 s time resolutions from a series of GPS receivers installed near the dip and low latitude regions does not show TEC enhancement during peak flare hours, 10:35 UT (16:05 IST). An appreciable enhancement in the TEC units (∼5 TEC units) is noticeable during post flare hours, 13:00 UT (18:30 IST) which is high at dip equatorial compare to low latitude regions. The Ionosonde measurement of 15 min time resolution at dip equatorial station shows an increase in the plasma density at the F-region while the E-region did not show any impact during peak flare hours, 10:35 UT (16:05 IST). The analysis of horizontal component of geomagnetic field (H) of 1 min time resolution data obtained from the INTERMAGNET shows sudden rise in electron density in the E-region of the ionosphere and intensification in the ionospheric current system in eastward direction at the dip equatorial and reverse in direction at low latitude regions at 10:35 UT (16:05 IST). Present analyses contribute our understanding about plasma dynamics during flare and post flare hours in the E and F-regions of Indian dip and low latitude Ionosphere.