Authors: Kara Kniezewski (Air Force Institute of Technology), Emily Mason (Predictive Science Inc), Johnathan Stauffer (Naval Research Laboratory), Daniel Emmons (Air Force Institute of Technology)

Magnetograms at the photosphere have been at the core of most efforts to identify signatures of imminent solar flares. Focusing on the photosphere is physically reasonable given that it is the only nearly continuous observable available of the solar magnetic field. However, in agreement with the Biot-Savart Law, the electric current systems that produce the photospheric magnetic field are inherently non-local. Here, Gauss’s separation method is applied to decompose the observed magnetic field at the photosphere into its components produced by currents above the photosphere in the chromosphere/corona, below the photosphere in the convection zone, and through the photosphere. This form of analysis, termed Carl’s Indirect Coronal Current Imager, or CICCI, is implemented to examine the evolution of coronal currents imprinted on the photosphere for 5 hours before an X-class flare in Active Region 11283. The fingerprints of coronal current fluctuations are detectable at the photosphere hours before the impulsive phase and are not present when the same active region is flare-quiet. Additionally, the pre-flare imprints of coronal currents are temporally correlated with the rapid and impulsive brightenings in plasma emission over the flux rope from Solar Dynamics Observatory Atmospheric Imaging Assembly EUV channels 94 Å, 131 Å, and 304 Å. These findings suggest that numerous localized, weak reconnection events take place within the hours before the impulsive phase. CICCI does not invoke assumptions on the non-local current sources and is therefore a powerful analysis tool to unveil coronal dynamics detectable at the photosphere before flare onset.