Modelling Solar Energetic Neutral Atoms from Solar Flares and CME-driven Shocks

TL;DR

This paper models the production and propagation of solar energetic neutral atoms (ENAs) from solar flares and CME-driven shocks, proposing ENAs as a new diagnostic tool to distinguish between different particle acceleration sites.

Contribution

It introduces a novel approach to use solar ENAs to differentiate between acceleration processes in solar flares and CME-driven shocks.

Findings

ENAs produced downstream of CME-driven shocks have distinct time profiles and spectra.

ENAs generated at large-scale flare loops show different observational signatures.

Solar ENAs can serve as probes to identify SEP acceleration sites.

Abstract

We examine the production of energetic neutral atoms (ENAs) in solar flares and CME-driven shocks and their subsequent propagation to 1 au. Time profiles and fluence spectra of solar ENAs at 1 au are computed for two scenarios: 1) ENAs are produced downstream at CME-driven shocks, and 2) ENAs are produced at large-scale post-flare loops in solar flares. Both the time profiles and fluence spectra for these two scenarios are vastly different. Our calculations indicate that we can use solar ENAs as a new probe to examine the underlying acceleration process of solar energetic particles (SEPs) and to differentiate the two accelertion sites: large loops in solar flares and downstream of CME-driven shocks, in large SEP events.