Dust distribution of the fiducial simulation at the start of planetesimal formation. The dust surface density σ_d is independent of the mass grid. The green contour indicates the drift limit, while the blue contour marks the fragmentation limit. White contours represent particle masses corresponding to Stokes numbers St = 1 (solid) and St = {10⁻¹, 10⁻², 10⁻³ } (dotted), respectively.