Year: 2026
Type: article
Abstract: Solar flares release a tremendous amount of magnetic energy that subsequently manifests in several forms; the bulk of this energy is transported through the Sun's atmosphere and explosively heats the chromosphere. While hard X-ray observations have pointed to flare-accelerated electrons as a primary means by which energy is transported following flares, alternative processes undoubtedly act alongside, or even instead of, those energetic electrons. To shed light on this we analysed flare-optimized, high-cadence Solar Orbiter observations. Footpoints from two flare ribbons were observed by the Spectral Imaging of the Coronal Environment (SPICE) instrument. Curiously, those footpoints exhibited contrasting behaviour: one had short-lived yet strong decreases in the Lyman β/Lyman γ line intensity ratio, whereas the other exhibited a more prolonged, moderate dip in that ratio. These observations were compared to synthetic spectra from radiation hydrodynamic simulations of flares driven by various energy transport mechanisms. This revealed that one footpoint was driven by energetic particle precipitation, while the other was driven by enhanced thermal heat flux. The implication is that energetic particles do not dominate along the entirety of flare ribbons. Critically, we must now focus on understanding where, when and why different mechanisms dominate in solar flare energy transport.
Source: Nature Astronomy
Institutions: Goddard Space Flight Center, Heliophysics Science Division, University of Glasgow, Catholic University of America, FHNW University of Applied Sciences and Arts Northwestern Switzerland, Space Sciences Laboratory, University of California, Berkeley, University College London, Dublin Institute For Advanced Studies, Queen's University Belfast, University of Colorado Boulder, National Solar Observatory, Southwest Research Institute, Northumbria University
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $12,690
Funders: National Aeronautics and Space Administration, UK Space Agency, Royal Society, Belgian Federal Science Policy Office, Centre National d’Etudes Spatiales, Nuclear Safety and Security Commission, Bundesministerium für Wirtschaft und Energie, Norsk Romsenter, Goddard Space Flight Center, Science and Technology Facilities Council
OpenAlex ID: W7118530435