General structure of the wind and MHD invariants. First panel shows the field lines in the internal and external disc. The grey dashed lines represent the surfaces at h/R = 0.3; 0.6 and 0.9. The three other plots display the MHD invariants for the internal field line (full, light blue) and the external one (semi-dashed, dark blue). The invariants are time averaged on the last 1000 orbits.