Studying the connection between coronal dimmings and flux rope footpoints using data-driven modelling and observations

Studying the structure of solar active regions through magnetic field modelling and observations strengthens our understanding of eruptive phenomena in the solar atmosphere. AR12975 featured an interesting event, where a significant restructuring of a pre-existing filament occurs approximately 1.5 hours before fully erupting. This event also shows clear signatures of coronal dimmings, which refer to a decrease in brightness in EUV and SXR observations of the Sun. They are interpreted as the density depletion caused by a coronal mass ejetion (CME) liftoff. As such, they are one of the most prominent low-corona signatures of CMEs and serve as important diagnostics for CME initiation and magnetic field reconfiguration after an eruption. Core dimmings, also known as flux rope dimmings, mark the footpoints of the erupting CME flux rope. To study them more in-depth we perform a time-dependent data-driven magnetofrictional simulation of AR12975. In particular, we focus on its magnetic structure and how the footpoints of the magnetic flux rope relate to the core dimming signatures observed in different EUV wavelenghts. To identify the magnetic flux rope from the model we use the Graphical User Interface for Tracking and Analysing flux Ropes (GUITAR). GUITAR uses a set of MFR proxies (here: combined maps of the twist parameter as well as the logarithm of the squashing factor) in combination with mathematical morphology operations to locate the MFR cross-section in a 2D plane. We also use GUITAR to disentangle the two flux systems that take part in the eruption.