6–10 Jul 2026
University of the Western Cape
Africa/Johannesburg timezone
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Polar Coronal Hole Size Variations Across Multiple Solar Cycles

9 Jul 2026, 14:40
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

JG Coertze (NWU)

Description

This study examines the evolution of polar coronal holes (PCHs), regions of open magnetic field in the solar corona, over Solar Cycles 24 and 25. Using AIA 193 Å observations and HMI magnetic-field measurements from the Solar Dynamics Observatory (SDO), variations in PCH morphology  and magnetic properties across the solar cycle are analysed. The results show that PCH area and occurrence are anti-correlated with solar activity, expanding during solar minimum and contracting during solar maximum, consistent with their role as tracers of the Sun’s global magnetic field. The agreement between modelled and observed magnetic flux further supports the reliability of coronal-hole connectivity studies. These results demonstrate the usefulness of PCHs as indicators of large-scale solar magnetic-field evolution.

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Author

Co-author

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

Presentation materials