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Session: Heliophysics and the Solar System

Name: Dr. Ioannis Kontogiannis (Leibniz Institute for Astrophysics Potsdam)
Coauthors: No coauthors were included.
Type: Oral
Title: The evolution of net electric currents in solar active regions hosting delta-spots
Abstract:

Active regions that host delta-spots, i.e., opposite magnetic polarity sports sharing the same penumbra, often produce the strongest flares and coronal mass ejections. Their highly complex magnetic field configurations require the presence of strong volume electric currents. This work presents new results regarding the development of these electric currents during flux emergence and the subsequent magnetic interactions within active regions. It utilizes a method based on image segmentation to determine more accurately the total unsigned non-neutralized (net) electric currents, Inn, injected to the corona. It has been found that Inn is significantly higher in strongly flaring regions, particularly before eruptive flares and strongly correlated with CME kinematic characteristics. The method is then applied on a sample of emerging active regions belonging to different magnetic complexity classes. Active regions with delta-spots contained systematically higher net electric currents. The temporal evolution of Inn exhibited intricate temporal evolution, with distinct events of increase, indicative of the various types of interactions between opposite magnetic polarities. The rate of increase of Inn during these events is strongly correlated with the flaring productivity of the source regions. In particular, active regions that produced X-class flares, such as NOAA 11158 and the superflaring region NOAA 12673, exhibited considerably higher rates of increase, as a consequence of strongly interacting opposite magnetic polarity partitions. The detailed study of net electric currents during these interactions can contribute to a better understanding of the origin of net electric currents in solar active regions.