Distribution of the polarization angle dispersion along FIR filaments at a spatial resolution of 18′. The peak at , annotated with a vertical line, indicates that many positions have significant deviations of polarization angles along the filaments. The black and red lines mark filaments with eigenvalues λ₋ < −1.5 K deg⁻², and blue andorange lines represent filaments limited to λ₋ < −3 K deg⁻².