Central goals of Solar Orbiter. These are to establish the physical links between the observed solar wind and its sources back on the Sun. The illustration shows some of the observed properties of fast wind from coronal holes and slow wind that may emanate from coronal hole edges, from loops beyond the coronal or the helmet streamer. The cut-out shows the complex magnetic structure modelled at the base of a fast wind flux tube that rapidly expands out of the chromosphere and into the corona. Understanding the dynamics of the solar magnetic atmosphere, and its signatures in the measured solar wind holds the key to understanding the sources of all solar wind (adapted from Tu et al. 2005; Schwadron & McComas 2003).