  We perform state-of-the-art, 3D, time-dependent simulations of magnetized
disk winds, carried out to simulation scales of 60 Astronomical Units, in order
to confront optical HST observations of protostellar jets. We ``observe'' the
optical forbidden line emission produced by shocks within our simulated jets
and compare these with actual observations. Our simulations reproduce the rich
structure of time varying jets, including jet rotation far from the source, an
inner (up to 400 km/s) and outer (less than 100 km/s) component of the jet, and
jet widths of up to 20 Astronomical Units in agreement with observed jets.
These simulations when compared with the data are able to constrain disk wind
models. In particular, models featuring a disk magnetic field with a modest
radial spatial variation across the disk are favored.
