Time-average half-thicknesses of the dust layer, 〈 H_dg〉, vs. time-average dust scale height, 〈 H_dust〉, with different values of R for runs of diffusion cases in the dynamic-dust simulations. The symbols correspond to runs with (Z_D2G, a) = (0.003, 10 μm) (circles), (0.01, 10 μm) (triangles), (0.03, 10 μm) (crosses), (0.1, 10 μm) (squares), (0.03, 30 μm) (pentagons), and (0.1, 30 μm) (stars). The dotted line marks the relationship of H_dg and H_dust following Eq. (22).