  We characterize the orientation of polar plumes as a tracer of the
large-scale coronal magnetic field configuration. We monitor in particular the
north and south magnetic pole locations and the magnetic opening during
2007-2008 and provide some understanding of the variations in these quantities.
The polar plume orientation is determined by applying the Hough-wavelet
transform to a series of EUV images and extracting the key Hough space
parameters of the resulting maps. The same procedure is applied to the polar
cap field inclination derived from extrapolating magnetograms generated by a
surface flux transport model. We observe that the position where the magnetic
field is radial (the Sun's magnetic poles) reflects the global organization of
magnetic field on the solar surface, and we suggest that this opens the
possibility of both detecting flux emergence anywhere on the solar surface
(including the far side) and better constraining the reorganization of the
corona after flux emergence.
