Mathematical Morphology applied to solar features detection

Mathematical Morphology (MM) is an effective method to identify different types of features visible on the solar surface such as sunspots, facular regions, and pre-eruptive configurations of Coronal Mass Ejections (CMEs), which are important indicators of the Sun’s activity cycle.  On the one hand, we determine sunspots areas in Solar Dynamics Observatory (SDO)/Atmospheric Imaging Assembly (AIA) intensity images with this MM method, and we compare the obtained values with existing solar databases (e.g., the Debrecen Heliophysical Observatory catalogue or Mandal et al.'s catalogue [2020, A&A doi:10.1051/0004-6361/202037547]). The good agreement between the MM results and the existing catalogues validates the method, which we then apply to contour the different magnetic polarities in the SDO/Helioseismic and Magnetic Imager (HMI) magnetograms in order to identify so-called delta-sunspots. The next step is to investigate the correlation between solar flares and the length of these delta-sunspots contours. On the other hand, as another application, MM also helps us to extract flux rope structures from magnetic field models, using twist number maps obtained from a time-dependent magnetofrictional code. We can then investigate the evolution of the magnetic flux rope properties and the underlying triggers for the instability that ultimately leads to an eruption.