  Context. HI filaments are closely related to dusty magnetized structures that
are observable in the far infrared (FIR). Recently it was proposed that the
coherence of oriented H i structures in velocity traces the line-of-sight
magnetic field tangling. Aims. We study the velocity dependent coherence
between FIR emission at 857 GHz and HI on angular scales of 18' . Methods. We
use HI4PI HI data and Planck FIR data and apply the Hessian operator to extract
filaments. For coherence we demand that local orientation angles {\theta} in
the FIR at 857 GHz along the filaments are correlated with the HI. Results. We
find some correlation for HI column densities at |v_LSR | < 50 km/s but a tight
agreement between FIR and HI orientation angles {\theta} exists only in narrow
velocity intervals of 1 km/s. Accordingly we assign velocities to FIR
filaments. Along the line of sight these HI structures show a high degree of
the local alignment with {\theta}, also in velocity space. Interpreting these
aligned structures in analogy to the polarization of dust emission defines an
HI polarization. We observe polarization fractions up to 80%, with averages of
30%. Orientation angles {\theta} along the filaments, projected perpendicular
to the line of sight, are fluctuating systematically and allow to determine a
characteristic distribution of filament curvatures. Conclusions. Local HI and
FIR filaments identified by the Hessian analysis are coherent structures with
well defined radial velocities. HI structures are also organized along the line
of sight with a high degree of coherence. The observed bending of these
structures in the plane of the sky is consistent with models for magnetic field
curvatures induced by a Galactic small-scale turbulent dynamo.
