Relative orientation parameter, ξ, as a function of particle density, n ≡ ρ/μ, in the simulations used in Soler et al. (2013). The values of ξ correspond to the relative orientation between ∇ρ and B in n-bins with an equal number of voxels, all with n> 500 cm^-3. The values ξ> 0 correspond to ∇ρ mostly perpendicular to B and ξ< 0 correspond to ∇ρ mostly parallel to B. The gray horizontal line is ξ = 0, which corresponds to the case where there is no preferred relative orientation between ∇ρ and B. The darker colors represent the early snapshots in the simulation and the lighter colors represent the later snapshots. The gray vertical line, drawn for reference, corresponds to n = 10⁴ cm^-3.