Outermost streamlines of the steady axisymmetric solution of the FFE jet (NMF07, TMN08), which are anchored to the event horizon (r = r_H) with the maximum colatitude angle at the footpoint θ_fp = π/2. A typical value of a = 0.9375 (in GRMHD simulations; Gammie et al. 2004; McKinney & Gammie 2004; McKinney 2006) is specified as a reference. The dotted line shows the genuine paraboloidal streamline with κ = 1.0 (z ∝ R² at R ≫ r_g; e.g., Blandford & Znajek 1977), while the solid line shows the paraboloidal streamline with κ = 0.75 (z ∝ R^1.6 at R ≫ r_g; e.g., Blandford & Payne 1982). The BH and the ergosphere are represented as the filled and hatched areas, respectively.