Radiative hydrodynamic simulations of first ionization potential fractionation in solar flares

Elemental abundances in solar flares are observed to vary both spatially and temporally, but the underlying mechanisms remain poorly understood. The interplay between advection and the preferential acceleration of low first ionization potential (FIP) elements likely shapes the observed abundance distributions. Models of the FIP effect predict enhancements near loop footpoints that diffuse upward over time. We simulate strong evaporation events that advect this low-FIP enhancement into the corona. When the enhancement is sharply peaked, the corona does not become fractionated, exhibiting only a localized abundance peak near the loop apex that facilitates coronal rain formation. By contrast, a broad enhancement with relatively weak heating yields a uniformly fractionated corona, which is not sufficient for coronal rain formation. As the heating rate increases, the low-FIP enhanced plasma is increasingly compressed towards the loop apex, and coronal rain is able to form. These results suggest a potential observational correlation between the presence and amount of coronal rain, the strength of flare heating and the fractionation process itself. This article is part of the Theo Murphy meeting issue 'Solar atmospheric abundances in space and time'.