Fiducial runs with k_turb = 2: maps of the gas density (top panels), cosmic-ray energy density (middle panels), and Alfvénic Mach number (bottom panels) in the plane z = 20 pc at a time corresponding to 2t_cross. From left to right panels: CR diffusion coefficient is D₀ = 10²², 10²⁴, 10²⁶, and 10²⁸ cm² s⁻¹. The arrows on the density maps represent the velocity vectors (normalised to a value of 14 km s⁻¹, see upper right panel), and the streamlines on the CR energy density maps represent the magnetic field lines, both in the xy-plane.