First Quantitative Results on the Response of Green and Red Line Dayglow Emissions to Solar Flares of Different Magnitudes

Abstract Flares originate from the impulsive release of magnetic energy in the solar atmosphere. The rise in X‐ray flux enhances ionization/electron content in the upper atmosphere, modifying the photochemical and dynamical processes that govern the ionosphere‐thermosphere behavior. Dayglow data from MIGHTI/ICON and Geostationary Operational Environmental Satellites X‐ray observations of more than 100 solar flares are used for statistical analysis in this study. We quantify the response of the twin‐peaks of (–) 557.7 nm (green‐line) at higher (F‐region) and lower (E‐region) altitude, as well as (–) 630.0 nm (red‐line) emissions, to solar flares in terms of percentage enhancements in peak and column‐integrated volume emission rate. Percentage enhancement of green‐line exceeds 100% (X‐class flares), whereas red‐line enhancements remain below 20%. The response of F‐region emissions does not scale solely with flare intensity but also depends on the location and duration of the flare. We also provide usable relationships to estimate the dayglow emission enhancements due to solar flares.