D-region in disturbed conditions, including flares and energetic particles

Abstract

A unified picture of the chemistry of the normal and the disturbed D-region is presented. Under disturbed conditions we include: (a) solar flares, (b) PCAs and (c) solar eclipses. The connecting thread is the six ion model of Mitra and Rowe, with appropriate modifications where necessary. Several areas of identity in the observational results of flares and PCAs are reviewed. These include: the dominance of q(O₂⁺) over q(NO⁺) due to X-rays in the first case and energetic particles in the second; drastic decrease in the effective loss coefficient during both flares and PCAs; disappearance of water cluster ions down to 73 km during day and 78 km at night during PCAs; the reversion of negative ions to their basic forms (O^- and O₂^-) during PCAs. For solar eclipses, the effects are essentially a mirror image of these due to flares and PCAs.