a) Equilibrium magnetic field in the y = 0, xz-plane. Dipoles are located at x = ± 0.5. X-point is located at x = 0 and . Red lines indicate the separatrices in this plane. b) 3D visualisation of the equilibrium magnetic field denoting the red separatrices along y = 0 from a) and perpendicular to this the blue X-line along x = 0 from c). Equilibrium magnetic field is rotationally symmetric about the y = 0 axis and thus black curves denote the separatrices in the xy-plane at z = 0. c) Equilibrium magnetic field shown in the x = 0, yz-plane. Magnetic field is only in the x-direction, hence no arrows. Blue line denotes the X-line of the form y² + z² = 2a². d) Plot of B_x(0,r) where r² = y² + z². B_x(0,r) changes sign at , i.e. at location of the X-line. Maximum of dB_x(0,r)/dr occurs at r = 1, where B_x(0,r = 1) = (4/5)^5/2 = 0.5724.