Refinement map produced with the refinement method outlined in Sect. 2.2 for the idealized situation of a diffuse bubble with a dense shell, designed to roughly resemble an SNR after shell formation. The solid-black, dashed-blue and dotted-green lines show the radial profiles of the refinement level, gas density, and ejecta fraction (scalar tracer field), respectively. The resolution is decreasing radially outward, levels off at l_{min, zoom} = 14 and increasing again to l_{max, zoom} = 18 inside the shell.