Authors: Ioannis Kontogiannis (Leibniz-Institute for Astrophysics Potsdam (AIP), Germany)

The emergence of magnetic flux often leads to complex magnetic field configurations, which carry strong electric currents and are usually the source of strong flares and coronal mass ejections (CMEs). In this work, we use the photospheric vector magnetograms provided by the Helioseismic and Magnetic Imager (HMI) instrument onboard the Solar Dynamics Observatory (SDO), to study the evolution of net electric currents during the emergence of magnetic flux and the subsequent magnetic interactions. To this end we use the method implemented by Georgoulis, Mikic & Titov (2012), which is based on image segmentation and error analysis to determine the magnetic partitions that carry non-neutralized electric current. Subsequently, the total unsigned non-neutralized electric current, Inn,tot, is determined for a sizeable sample of active regions, with varying magnetic complexity. It is found that Inn,tot is strongly associated with the presence of sheared magnetic polarity inversion lines and it is a very good indicator of subsequent flaring productivity, exhibiting a strong correlation with the kinematic properties of coronal mass ejections, in the case of eruptive flares. The time series of Inn,tot show more intricate structure than the total unsigned vertical electric current density ones, prompting further investigation. Although the long-term evolution of Inn,tot shares some common characteristics with the evolution of the magnetic flux, a short-term evolution is superposed, in the form of distinct peaks and valleys, indicating the act of electric current injection events. A statistical analysis of these events shows that the injection events do not necessarily coincide with increasing magnetic flux, which indicates that they may stem from the interactions between magnetic partitions. The increase rates and durations of the events are higher with increasing complexity of active region, with regions containing delta-spots exhibiting the strongest ones. The future goal is to utilize the time series of non-neutralized electric currents to further understand the emergence of magnetic flux and the interactions between partitions, as well as their relative importance in the build-up of electric currents, and explore how these results can facilitate the prediction of flares and CMEs.