Evolution of Non-neutralized Electric Currents in Eruptive Solar Active Regions

We study the evolution of three solar active regions (ARs) that produced both fast (>600 km/s) and slow (<600 km/s) coronal mass ejections (CMEs). We analyze the vector magnetic field measurements to derive temporal evolution and spatial distribution of vertical electric currents in the active regions during their disk passage. Our preliminary results indicate the growth of non-neutralized electric currents, during which, CMEs are produced. We have also conducted a detailed case study of the electric current evolution in NOAA AR 11305, which produced an M-class eruptive flare. Strong non-neutralized currents, associated with emerging flux and shear flows, were located along the magnetic polarity inversion line. The observations suggest the presence of a magnetic flux rope (MFR), which evolved and erupted, forming flare ribbons that encompass the areas of strong current. The regularized Biot-Savart laws (rBSLs; Titov et. al. 2018) formalism and a zero-β magnetohydrodynamic (MHD) model were employed to construct the aforementioned MFR and to follow its evolution. The spatial location and the amount of non-neutralized currents computed from the model agree with the observational measurements. This result suggests that the development of the MFR, which is associated with sustained and concentrated photospheric non-neutralized electric currents, is an important element for the production of the CME in this study. This work is supported by NASA programs HSR (80NSSC20K1317) and HGI (80NSSC18K0622).