Poloidal cuts through model N3d-VF, with colour-coded and vectors indicating the in-plane field. Panel a), at t = 2.7 Gyr, shows the initial A0 mode and strong fields created by the combined action of MRI and convection outside R ≃ 10 kpc. In panel b), at t = 3.9 Gyr, the S0 appears, and MRI is now somewhat weaker.