Polarisation and magnetic field maps: circular polarisation of Fe I 6302 Å at Δλ = −0.08 Å (panel a) and Ca II 8542 Å at Δλ = −0.29 Å (panel b). Line-of-sight magnetic field strength obtained from the Fe I 6301–6302 Å (panel c) and Ca II 8542 Å lines (panel d). Vertical magnetic field strength for the Fe I 6301–6302 Å (panel e) and Ca II 8542 Å lines (panel f). In panel b, the red arrow indicates the north and the green arrow the disk centre. The points indicated with 1, 2, and 3 refer to Fig. 1. The dashed rectangle and the black arrow of panel e refer to Fig. 4. The black arrows in panel f indicate the direction of the horizontal field.