Analysis of solar EUV and X-ray flux enhancements during intense solar flare events and the concomitant response of equatorial and low latitude upper atmosphere

We investigate the X ray and UV flux changes during flare events and the corresponding ionospheric response. The study reveals that UV flux enhancement depends on both flare intensity and position on solar disk while X-ray flux enhancement depends only on the former. The study brings out a new result that the E region response to flares directly relates to the X-ray flux enhancement and that it does not exhibit limb effect. Further, the F region response shows limb effect indicating the UV flux control on the same and it also shows seasonal variability due to solar zenith angle variability.

► E region response to flare events is directly related to the X ray flux enhancement and not to UV flux increase.
► E region response does not show any limb effect confirming that it is being controlled by the X-ray flux which also does not exhibit limb effect.
► TEC response to flares is greater at equatorial regions during winter and equinox than at northern low latitude stations, whereas during summer it is greater at northern low latitude regions compared to equatorial regions.