Evolution of Photospheric Magnetic Field and Electric Currents during the X1.6 Flare in Active Region NOAA 12192

Abstract: The dynamics of magnetic fields in the Sun's active regions plays a key role in triggering solar eruptions. Studies have shown that changes in the photosphere's magnetic field can destabilize large-scale structure of the corona, leading to explosive events such as flares and coronal mass ejections (CMEs). This paper delves into the magnetic field evolution associated with a powerful X1.6 class flare that erupted on October 22nd, 2014, from the flare-rich active region NOAA 12192. We utilized high-resolution vector magnetograms from the Helioseismic and Magnetic Imager (HMI) on NASA's Solar Dynamic Observatory (SDO) to track these changes. Our analysis reveals that a brightening, a precursor to the flare, began near the newly emerged, small-scale bipolar flux regions. During the X1.6 flare, the magnetic flux in both polarities displayed emergence and cancellation. The total current within the active region peaked during the flare. But, it is a non CME event and the ratio of direct to return current value remain close to 1. The large flare in this active region occured when the net current in both polarities attain the same sign. This implies that the Lorentz force, a consequence of the interaction between currents and magnetic fields, would have pushed the field lines together in this scenario. This reconnection of opposing magnetic fields is believed to be the driving force behind major flare occurred in this active region.