Details of penumbral fine structure in the upper chromosphere. a) I_c, b) (I_c−I_He) /I_c, c) B, d) γ, e) φ, and f) υ_LOS. The location of the maps is indicated by a box in the fourth map of Fig. 3b. Contours in panels a)– f) depict γ = 110°and125°. Panel g) depicts variations in γ along the white line marked in panel d). Blue circles identified as A–E in panel g) represent locations of observed and synthesized Stokes profiles of the Hei triplet plotted in Fig. 5.