Schematic view of the vertical structure of the magnetic field in penumbral filaments following Zakharov et al. (2008). Depicted is a plane perpendicular to the filament. The filament is represented by the semicircular area. The crosses in the circular white areas indicate the direction of the magnetic field in the penumbral filament, which is perpendicular to the plane of the drawing. Yellow arrows indicate the overturning convection within the filament and red arrows depict the field reversal at the edges of the filaments, which is caused by the convective flow through advection of the filament’s field. Only the projected component of the field, which is directed mainly into the page even for the red arrows, is plotted. The background magnetic field (spines) is indicated by nearly vertical black arrows. Dashed lines show different log τ levels. Lighter and darker shades of blue correspond to weaker and stronger B, respectively.