Temporal evolution of physical parameters. From left to right: G-band intensity, LOS velocity, field strength, and inclination. The time indicated in the bottom left corner corresponds to the instant when the SP slit was over the BSF. The thin blue contour outlines the BSF and corresponds to −0.2 km s^-1. Panel numbers are shown in the top left corner. Five azimuthal cuts at different radial distances and indexed 1–5 are indicated in panel 1. The plot also shows two radial lines passing through the BSF and RSF.