MHD simulations and the corresponding synthetic Stokes I maps. Top row: B_Z in kG of the MURaM simulations at a height of z = 0.85 Mm above the bottom layer of the simulation box, which approximately corresponds to the visible surface layer. From left to right: snapshots of simulations with different initially imposed mean vertical magnetic fields of ⟨B_Z⟩ = 30, 50, 100 and 200 G. Second row to bottom row: Synthetic Stokes I/I_c maps at dλ = −0.35 Å for the Fe I 6173.3 Å absorption line for μ = cos(θ) decreasing from = 1.0 to μ = 0.15. For μ < 1 the y axis is foreshortened. The I/I_c maps are saturated from 0 to 1.5 units of the average continuum intensity, I_c, at μ = 1. The maps at μ = 0.9 and 0.8 are omitted for brevity.