6–10 Jul 2026
University of the Western Cape
Africa/Johannesburg timezone
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Detailed study of a solar flare: photospheric deformation and chromospheric/coronal connectivity

9 Jul 2026, 15:00
20m
Lecture Hall C3 (University of the Western Cape)

Lecture Hall C3

University of the Western Cape

Oral Presentation Track D - Astrophysics & Space Science Astrophysics & Space Science

Speaker

Ruhann Steyn (Centre for Space Research, North-West University)

Description

Solar observations provide a wealth of data at high resolution in all layers of the solar atmosphere, obtained from ground-based and space-born observatories. A multi-layer analysis of a C-class flare observed on 1 July 2012 is presented using high-resolution Swedish 1-m Solar Telescope (SST) observations, SDO/HMI SHARP data, SDO/AIA imaging, and potential field extrapolations. The chromospheric structure, flare ribbon positions, fine-scale polarity inversion line (PIL), photospheric velocity flows and the components of the rate-of-strain tensor are strongly co-spatial. This indicates that the flare occurred within a well-defined area of photospheric deformation. The extrapolated magnetic field lines are rooted across the PIL, with opposite footpoints embedded in distinct flow streams and different local strain environments, consistent with differential stressing. The field lines are spatially consistent with the chromospheric and ultraviolet flare ribbons observed in SST Hα and AIA 1700 Å, linking the photospheric deformation to the overlying flare geometry. The combined observations strongly suggest that localised strain and shear flow around the PIL contribute to the magnetic field evolution before and after the flare. This event therefore provides a compelling example of how fine-scale photospheric deformation can organise flare-relevant magnetic connectivity from the photosphere into the chromosphere and lower corona.

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Author

Ruhann Steyn (Centre for Space Research, North-West University)

Co-authors

Ms Calmay Lee (North-West University, Centre for Space Research) Prof. Eamon Scullion (Northumbria University) Dr Gert Botha (Northumbria University) Dr Stephane Regnier (Northumbria University)

Presentation materials

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