Saturated Toomre parameter ⟨Q⟩ (solid black, left axis) and box-averaged mass density ⟨ρ⟩ (dashed blue, right axis). At tΩ₀ = 600, sg-mhd-1 was restarted, with ⟨ρ⟩ held constant from then on (sg-mhd-2). Therefore, the values of ⟨ρ⟩ start to deviate between sg-mhd-1 and sg-mhd-2 at tΩ₀ = 600. Similarly, the values of ⟨Q⟩ also begin to deviate at tΩ₀ = 600. For sg-mhd-1, ⟨Q⟩ slightly increases, and for sg-mhd-2, ⟨Q⟩ stays almost constant.