  The smooth soft X-ray excess seen in many type-1 AGN can be well described by
models of absorption in partially ionized material with a large velocity
dispersion, often physically interpreted as a radiatively driven accretion disk
wind. However, the state-of-the-art XSCORT code, which calculates the
photoionized radiative transfer through a differentially outflowing absorber,
shows that terminal velocities of order ~0.9c are required in order to
reproduce the soft X-ray excess. Such a high outflow velocity rules out UV-line
driving, continuum radiation driving, and thermal driving as mechanisms for
producing the wind. Entrainment of material by the magnetically driven jet is
the only plausible origin of such a high velocity flow, but numerical
simulations of jets and associated outflows do not currently show sufficient
material at high enough velocities to reproduce the soft X-ray excess. If the
soft excess is produced by absorption then it seems more likely that the
material is clumpy and/or only partially covers the source rather than forming
a continuous outflow.
