  We have proposed a viscoelastic model of the Maxwell stresses due to the
disorganized magnetic field in MRI-driven MHD turbulence. Viscoelastic fluids
in the laboratory are known to produce jet-like structures under the action of
a rotating sphere. Here we argue that a similar mechanism may help explain jets
in protostellar systems. Such jets would be driven not by large-scale organized
magnetic fields, but by the mean-field stresses of small-scale tangled magnetic
fields.
