Constraining the Properties of the Acceleration Region Plasma Environment with Solar Energetic Electrons

Impulsive solar energetic electrons (SEEs) detected in the heliosphere are widely accepted to originate in flaring coronal events. However, it is unclear what conditions lead to their acceleration, or their connection to non-thermal hard X-ray emitting electrons observed in similar events. We perform simulations of an injected non-thermal electron distribution into a hot overdense coronal region representing the flare, with varying plasma parameters, which is then propagated through the heliosphere out to 1.0 AU. We investigate how changes in the coronal temperature, number density and physical region size affect SEE fluence and flux in the heliosphere, to resolutions comparable with instruments onboard current spacecraft such as Solar Orbiter. We find that features of the low-energy (1-20 keV) fluence spectra vary significantly according to coronal plasma parameters. This demonstrates that signatures in the heliospheric low-energy flare electron spectra observable with current data could be used to constrain the plasma parameters of acceleration regions and by extension the location of regions from which energetic flare particles originate.