Evolution of AR NOAA 12280 on February 3–5, 2015. Top panels: HMI magnetograms, bottom panels: AIA 171 images. The emergence of magnetic bipoles is clearly visible in the neighbourhood of the AR and near the jet base. Two examples: the red circle in the top panels a,b indicates a new emerging bipole on February 3; this was followed on February 5 by an another emerging bipole marked by the blue oval (panel b). The green and red contours are the HMI magnetic field contours of ±100 Gauss in strength, respectively. The images are aligned together at 20:50 UT on February 5, 2015. The blue square is the FOV of Fig. 3.