When Magnetic Field Lines Stretch, Snap, and Expand: A New Look at Solar Flares with L-maps Journal Article uri icon

Overview

abstract

  • Abstract; ; Understanding the three-dimensional evolution of coronal magnetic fields during solar flares remains challenging due to the lack of direct coronal field measurements. Here, we combine data-driven MHD simulations of NOAA AR 11158 with flare-ribbon and coronal-dimming observations to investigate realistic coronal magnetic-field evolution during an X-class flare. We introduce; L-maps; —maps of natural logarithm of magnetic field-line lengths—as a diagnostic tool to track the dynamics of simulated coronal magnetic structures. Variations in L-maps identify flare ribbons through field-line shortening and coronal dimmings through field-line lengthening. Comparison with Solar Dynamics Observatory/Atmospheric Imaging Assembly observations demonstrates strong morphological and temporal agreement, validating the simulated field evolution. Applying K-means clustering to the L-map temporal profiles, we distinguish three stages of coronal evolution: (1) slow preflare rise phase, (2) flare reconnection accompanied by coronal mass ejection (CME) rise, and (3) post-reconnection CME expansion. We detect a slow preflare rise phase of magnetic field lines routed in ribbon footpoints and identify; reconnection dimming; —an area of rapid expansion of active-region core magnetic field lines during the flare impulsive phase due to reconnection. Our results show that L-maps provide a powerful and physically intuitive framework for bridging simulations and observations and for tracking the full three-dimensional evolution of coronal magnetic fields during flares.;

publication date

  • March 1, 2026

Date in CU Experts

  • March 5, 2026 6:46 AM

Full Author List

  • Kazachenko MD; Fan Y; Afanasyev AN

author count

  • 3

Other Profiles

International Standard Serial Number (ISSN)

  • 0004-637X

Electronic International Standard Serial Number (EISSN)

  • 1538-4357

Additional Document Info

start page

  • 137

end page

  • 137

volume

  • 999

issue

  • 1