Optical depth stratification of various physical parameters of the standard filament displayed in Fig. 11 perpendicular to its axis. Panels in the first, second, and third column represent the head, middle, and tail of the filament, respectively. From top to bottom (for each column): T, B, γ, the vertical component of the magnetic field | B_z |, the radial component of the magnetic field B_r, and (ΔB/ Δlog τ). The head, middle, and tail positions are marked by dashed vertical lines in Fig. 11.