Specific angular momentum r × v_ϕ vs. poloidal velocity V_p, both normalized to . Red symbols show the values derived for the HH30 CO cavity while curves show the expected relations from steady self-similar MHD disk winds launched from radii r₀ = 0.1, 0.5, 1, 1.5, 2, 2.5, 3 au (full curves) with magnetic lever arm λ = 1.5, 1.6, 2.0, and 3.0 (dashed curves). Figure adapted from Ferreira et al. (2006).