Contributed by Chia-Hsien Lin. Posted on August 17, 2022
This study reveals that a significant number of coronal-hole field lines extend beyond the coronal-hole boundaries and that many coronal-holes contain no open magnetic field lines.
Contributed by Kelvin Moresi. Posted on August 10, 2022
Compactness is one geometric property of a sunspot group that has not yet been systematically quantified. We calculate the compactness of a small sample of δ-spots and β-spots using a minimum bounding circle. On average, the δ-spots are found to be more than twice as compact as the β-spots.