Oscillation time series. Top: evolution of the detrended normal velocity component at the bundle apex averaged over the oscillating field lines in the bundle. The best-fit is shown in red. Middle: evolution of the Joule (dashed line) and viscous volumetric heating rate (dotted line) at the bundle apex. Bottom: temperature (black), the x-component of the vorticity averaged in the vicinity of the bundle apex (solid blue line) and the z-component of the vorticity averaged in the vicinity of the right bundle footpoint (dotted blue line). The time intervals correspond to the time ranges highlighted in blue in Figs. 3 and 4.