Validation of an Extreme-ultraviolet Desaturation Technique for the Atmospheric Imaging Assembly on Board the Solar Dynamics Observatory Using Observations from the Extreme Ultraviolet Imager on Board Solar Orbiter

Le résumé fourni par la source

Abstract High-dynamic-range imaging in the extreme-ultraviolet regime is frequently compromised by detector saturation and charge blooming during intense solar flares, preventing reliable photometry of flare cores. This study presents, for the first time, a direct validation of a sparsity-regularized inverse-diffraction desaturation algorithm applied to saturated images from the Atmospheric Imaging Assembly on the Solar Dynamics Observatory, using contemporaneous short-exposure, unsaturated observations from the Extreme Ultraviolet Imager on Solar Orbiter. The validation exploits a near-radial spacecraft alignment on 2024 March 19, when an M2.1 flare erupted in active region 13615. To obtain coregistered intensity maps, the data were processed with reprojection onto a common helioprojective grid, exposure-time normalization, light-travel-time correction, and field-of-view pointing refinement. Photometric comparisons were performed using peak-based statistics within a rigorously defined region of interest. Results show close morphological agreement and a temporally stable ratio between the desaturated and reference intensities through the impulsive and early decay phases. An early-phase discrepancy is observed and attributed to rapid subexposure evolution, sampling effects, and bandpass/response differences. These findings demonstrate that the desaturation procedure successfully recovers physically meaningful time-dependent core fluxes and, for the first time, provide independent empirical support for the use of desaturated archive frames in quantitative studies of large flares.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.