Relative orientation of the gas velocity and magnetic fields in a slice at ɀ = 0 in our fiducial CHEM_MHD simulation at t = 186 Myr. A snapshot at early time is chosen here to show the orientation in the dust lanes as well, which are depleted at later times. The colour-scale indicates cos α defined in Eq. (19), where cos α = 1 and cos α = 0 correspond to В and v being parallel and perpendicular respectively. Streamlines with red arrows trace gas velocity in the frame co-rotating with the bar. The plot is separated into two panels for densities n > 20 cm⁻³ (top) and n < 20 cm⁻³ (bottom) for clarity. Velocity and magnetic fields are well aligned in the less turbulent regions (cos a close to 1), while their orientation becomes progressively more random in regions where the turbulence is dynamically more important.