The same as Figure 13 for the total magnetic energy stored in unit length of the tail, dW _B/dX from the BATSRUS model runs at simulation time t = 90 min. As for the magnetic flux in the tail, the sum of the two is lower for the ϕ = +35° case than the ϕ = 0 case. The total energy W _B over the 15 R _E length shown is 20% larger for the ϕ = 0 case which is a larger effect than the 5% effect found using the empirical magnetopause model (see Fig.5).