Randomly selected dust trajectories for a₀ = 0.1, 4, and10 μm (left, middle, and right panels, respectively). The trajectory color represents the local value of the Stokes number. Entrained dust grains, launching from the launching region (black), migrate upwards on the colorbar the as they move to regions of lower gas density. Gas streamlines are shown in dash-dotted grey. (For all simulated grain sizes, see Fig. C.1.)