Speaker
Description
First Name: Meriem
Last Name: Alaoui
Affiliation: IREAP/UMD & NASA/GSFC
All Authors Meriem Alaoui
Abstract: Hard X-ray (HXR) spectra of solar flares are usually interpreted with the standard collisional thick-target model (CTTM), but return-current (RC) losses can substantially modify electron transport and bias the inferred nonthermal energy. Using my RunRC code, which self-consistently couples a beam of flare-accelerated electrons to the co-spatial return current, I examine a multi-burst X-class flare with multiple HXR peaks. Time-dependent imaged and spatially-integrated spectral fits are compared with CTTM and RC thick-target solutions. Additionally, the level of co-spatial turbulence and the source of turbulence are investigated. I will show that the relative importance of RC losses varies strongly between bursts: some intervals are RC-dominated, while others are well described by purely collisional transport but result in strong constraints on the acceleration and transport mechanisms. This event provides strong constraints on plausible beam and return-current (background) plasma conditions and identifies a regime where the standard CTTM fails to account for the observed HXR emission. More broadly, this case study illustrates how transport-constrained modeling with RunRC, combined with basic imaging information, can narrow the range of acceptable nonthermal energetics and guide future flare studies and modeling of high-energy flares.