Magnetic field structure of AR 11504 and its surroundings for June 14, 2012, event. Left: Blend of snapshots of SDO/AIA 193 Å and the HMI line-of-sight magnetogram. The active region of interest and the suspected semi-open structure are highlighted by the blue circle. Right: Characteristic field lines of a PFSS extrapolation created with the https://suntoday.lmsal.com by LMSAL are based on the models described in Schrijver & De Rosa (2003). Open field lines (magenta lines) are present at the east of the active region of interest (marked with a blue circle), close to the location where we suspect a CH/open magnetic field structure, based on the dimming recovery behavior.