Vertical density profile of the millimetre dust simulated at 30 AU (St ≃ 0.025) and comparison with ALMA observations. The red profile corresponds to our simulation with β = 10³ and ambipolar diffusion (Am = 1). The purple profile is that obtained in the ideal (zero net flux) MRI simulation of Fromang et al. (2006) for the same Stokes number. The orange area corresponds to the range of profiles compatible with the 0.87–2.9 mm dust continuum emission measured by ALMA (Pinte et al. 2016). To help the comparison, the density profiles are all normalized with ρ₀ = 1; the gas profile is represented by a blue line. The x-axis unit is in AU, the conversion is about 1H ≃ 2.5 AU at R = 30 AU.