Initial background density (plotted on a log scale) in the full simulation domain at an azimuthal slice φ = 0, shown in panel a. The positions of field lines 1, 2 and 3 indicated are used for discussion in the text. Contours for the plasma-β = 1 layer and transition region are shown by the green and grey lines, respectively. Panel b shows the initial magnetic field strength and topology outlined by the black dashed box in panel a. The same configuration is found for all azimuthal angles due to the symmetry of the background equilibrium around the central axis. The location and strength of the (asymmetric) wave driver is highlighted by the purple bar on the horizontal axis. Panel c gives the location of the wave driver employed with r₀ = 7 Mm (displayed on a Cartesian grid). The strength of the driver is shown in arbitrary units.