PFSS extrapolation obtained on February 4 at 12:04 UT. In the PFSS extrapolation, purple and green indicate open field lines of negative and positive polarity, respectively. White is used for closed field lines. In the magnetogram, regions of strong positive (negative) magnetic field are shown in white (black). The magnetic connection of the eruption region, given by the cross, to the location of the dimming, given as red shaded area, is illustrated by an arc tracking a field line. The starting height of the extrapolation is 1.2R₀.