Example of a solution satisfying all observational constraints on the polar magnetic field: temporal variation and latitudinal profiles for u₀ = 10 m s⁻¹, η = 600 km² s⁻¹ and τ = 7 yr (Flow 1). Time variations of various quantities are shown in the left panel: in the label of the dotted curve B refers to the field amplitude at the pole; vertical dashed lines mark the reversals of the WSO polar field. Right panel: latitudinal profile of the magnetic field at various instants as indicated; vertical dashed lines mark the latitudes where B equals half its value at the poles at cycle minimum.