Contour of constant electric field intensity $\stackrel{\sim }{E}=E_c$ (solid blue curve), in the x-z plane of Kerr-Schild, Cartesian coordinates. The black-filled disk is the Kerr BH horizon. In this example, the BH spin parameter is ξ = 0.5 and magnetic field strength β = 200, which corresponds to B₀ = 8.8 × 10¹⁵ G. The dashed gray lines show the ends of the polar lobes which have a semi-aperture spherical polar angle ${\theta }_p\approx arccos(\sqrt{3}/3)\approx 55°$.