Effects of a Solar Flare on the Martian Hot O Corona and Photochemical Escape

We examine for the first time the flare-induced effects on the Martian hot O corona. The rapid ionospheric response to the increase in the soft X-ray flux (similar to 800%) facilitates more hot O production at altitudes below the main ionospheric peak, but almost all of these atoms are thermalized before escape. In response to the increase in the extreme ultraviolet (EUV) flux (similar to 170%), the overall upper ionospheric and thermospheric densities are enhanced, and the peak thermospheric responses are found similar to 1.5 hr later. The photochemical escape rate is predicted to increase by similar to 20% with the increases in the soft X-ray and EUV fluxes but decrease rapidly by similar to 13% about 2.5 hr later before recovering the preflare level. Since escaping hot O atoms are mostly produced at high altitudes where ionization by the EUV flux is the greatest, the main contributor to the 20% increase in escape rate is the enhancement in the EUV flux.