  By comparing a magneto-frictional model of the low coronal magnetic field to
a potential-field source-surface model, we investigate the possible impact of
non-potential magnetic structure on empirical solar-wind models. These
empirical models (such as Wang-Sheeley-Arge) estimate the distribution of
solar-wind speed solely from the magnetic-field structure in the low corona.
Our models are computed in a domain between the solar surface and 2.5 solar
radii, and are extended to 0.1 AU using a Schatten current-sheet model. The
non-potential field has a more complex magnetic skeleton and quasi-separatrix
structures than the potential field, leading to different sub-structure in the
solar-wind speed proxies. It contains twisted magnetic structures that can
perturb the separatrix surfaces traced down from the base of the heliospheric
current sheet. A significant difference between the models is the greater
amount of open magnetic flux in the non-potential model. Using existing
empirical formulae this leads to higher predicted wind speeds for two reasons:
partly because magnetic flux tubes expand less rapidly with height, but more
importantly because more open field lines are further from coronal-hole
boundaries.
