Narval time series of circularly polarised Stokes profiles. Observations are shown as black dots and ZDI models as red lines, and they are offset vertically for better visualisation. The number on the right indicates the rotational cycle (see Eq. (1)). All signatures are antisymmetric, indicating that we are seeing the negative polarity of a dipole, and the moderate variation in amplitude is symbolic of a small tilt of the magnetic axis.