Stream functions ψ of selected modes for m = 2, using the solar surface differential rotation profile and the Ekman number E = 4 × 10⁻⁴. The solid curves show the real parts, and the dashed curves illustrate the imaginary parts. In each case, the normalization is such that ψ = 1 where |ψ| is maximum (this happens at different latitudes depending on the mode). In each panel, the name of the mode and the real part of its frequency are given (see also Fig. 2e). The vertical red arrows give the latitudes of the viscous layers.