Snapshot of the nonaxisymmetric azimuthal field during the linear growth of the instability (t − t_pert = 22) for the run in Fig. 5. (a) Meridional cut at longitude ϕ = 90°. The curved dashed line shows radius r/r_o = 0.9 where the magnetic energies of Figs. 5a,b are calculated. (b) Azimuthal cut at colatitude θ = 85° passing through a local maximum of (shown as an oblique dashed line in (a)).