  The study concerns the streamer belt observed at high spectral resolution
during the minimum of solar cycle 22 with the Ultraviolet Coronagraph
Spectrometer (UVCS) onboard SOHO. On the basis of a spectroscopic analysis of
the O VI doublet, the solar wind plasma parameters are inferred in the extended
corona. The analysis accounts for the coronal magnetic topology, extrapolated
through a 3D magneto-hydrodynamic model, in order to define the streamer
boundary and to analyse the edges of coronal holes. The results of the analysis
allow an accurate identification of the source regions of the slow coronal wind
that are confirmed to be along the streamer boundary in the open magnetic field
region.
