Reduced quantities as a function of the BH spin. Top panel: ISCO (solid green line), event horizon (solid black line), and ergosphere at the equator (dashed black line) as a function of the BH spin. The blue line indicates the approximate location of the footpoint of the separatrix found by Uzdensky (2005), and the blue squares are the values measured in our simulations. Middle panel: magnetic flux Φ_jet of the open magnetic field lines threading the event horizon (green, left axis). In blue (right axis) are the jet electromagnetic powers measured (squares) and predicted by Tchekhovskoy et al. (2011) (crosses). Bottom panel: angular momentum (left axis) and energy (right axis) transferred from the BH to the disk per unit time, with and without the force-free approximation (crosses and squares).