The chromosphere during solar flares

TL;DR

This paper reviews the role of the chromosphere in solar flares, emphasizing its diagnostic importance and discussing energy transport and electron acceleration mechanisms in flare models.

Contribution

It provides a comprehensive review of chromospheric signatures in solar flares and explores alternative energy transport and electron acceleration processes.

Findings

Chromospheric emission offers key diagnostics for flare energy components.

Challenges exist in applying diagnostics within the standard flare model.

Proposes ideas on energy transport and electron acceleration in flare chromospheres.

Abstract

The emphasis of observational and theoretical flare studies in the last decade or two has been on the flare corona, and attention has shifted substantially away from the flare's chromospheric aspects. However, although the pre-flare energy is stored in the corona, the radiative flare is primarily a chromospheric phenomenon, and its chromospheric emission presents a wealth of diagnostics for the thermal and non-thermal components of the flare. I will here review the chromospheric signatures of flare energy release and the problems thrown up by the application of these diagnostics in the context of the standard flare model. I will present some ideas about the transport of energy to the chromosphere by other means, and calculations of the electron acceleration that one might expect in one such model.