We present polarization profiles observed with the HAO/NSO Advanced St
okes Polarimeter (ASP) that demonstrate, in a model-independent way, t
he presence of strong downflows close to the neutral line of a delta s
unspot (a spot with both polarities contained within the same penumbra
). The flows are as large as 14 km s(-1), a velocity that, at photosph
eric levels, strongly suggests the presence of supersonic compressive
fluid flows in a region only 100-200 km above the visible surface. The
se velocities are probably the largest ever reported at photospheric l
evels. The region containing the downflows is large enough (about 2''
on a side) to be resolved, although it is likely to contain fine struc
ture at or below our spatial resolution. The origin of these flows is
discussed in terms of the funneling of material through an isolated ma
gnetic nozzle in an otherwise closed magnetic system which is rising t
hrough the surface.