Overview

• The Daniel K. Inouye Solar Telescope captured the decay phase of an X1.3 flare on August 8, 2024 using its Visible Broadband Imager at the H-alpha wavelength.
• Measured loop widths averaged roughly 48 kilometers with the thinnest features near 21 kilometers, approaching the instrument’s practical resolution limit of about 24 kilometers.
• The observation marks DKIST’s first recorded X-class flare, achieved under favorable conditions that maximized image clarity.
• The results were published August 25, 2025 in The Astrophysical Journal Letters as “Unveiling Unprecedented Fine Structure in Coronal Flare Loops with the DKIST.”
• Scientists say the unprecedented fine-scale detail can test theories of magnetic reconnection and refine flare models, with potential to improve space-weather forecasting as more events are analyzed.