Magnetic field of a relativistically rotating neutron star and its magnetosphere for the global twist model. The field lines are shown in black, the stellar surface in green, and the light cylinder with a dashed blue line at R = 1; the current sheet is also shown. The red line represents the first closed field line of the untwisted case (panel a) and is shown in subsequent panels for comparison. A poloidal current is applied in the area of the closed magnetic field lines with coefficients α = 0.0,  3.0,  6.0, and 8.0. The colour bar indicates the value of II′ across several parts of the star and the magnetosphere. The maximum value of II′ in the twisted field lines is saturated in colour to allow the depiction of its structure in the rest of the system. The top-right inset is shows a zoomed-in area of the star.