Value of the inclination (panel a), azimuth (panel b), and strength (panel c) of the magnetic field obtained from Fe I 6301–6302 Å (black curve) and Ca II 8542 Å data (blue curve) averaged inside the dashed box of Fig. 2e along the direction indicated by the black arrow of Fig. 2e. Vertical magnetic field corresponds to an inclination of 90°. The zero azimuth is defined with respect to the westerly direction (counterclockwise).