  We present self-similar models of resistive viscous Keplerian disks driving
non-relativistic magnetohydrodynamics (MHD) jets becoming super
fast-magnetosonic. We show that in order to obtain such solutions, the thermal
pressure must be a sizeable fraction of the poloidal magnetic pressure at the
Alfven surface. These steady solutions which undergo a recollimation shock
causally disconnected from the driving engine, account for structures with a
high temperature plasma in the sub-Alfvenic region. We suggest that only
unsteady outflows with typical time-scales of several disk dynamical
time-scales can be produced if the suitable pressure conditions are not
fulfilled.
