Relativistic AGN jets I. The delicate interplay between jet structure,
  cocoon morphology and jet-head propagation
  Current observations have shown that astrophysical jets reveal strong signs
of radial structure. They suggest that the inner region of the jet, the jet
spine, consists of a low-density, fast-moving gas, while the outer region of
the jet consists of a more dense and slower moving gas, called the jet sheath.
Moreover, if jets carry angular momentum, the resultant centrifugal forces lead
to a radial stratification. Current observations are not able to fully resolve
the radial structure, so little is known about its actual profile. We present
three AGN jet models in $2.5D$ of which two have been given a radial structure.
The first model is a homogeneous jet, the only model that doesn't carry angular
momentum; the second model is a spine-sheath jet with an isothermal equation of
state; and the third jet model is a (piecewise) isochoric spine-sheath jet,
with constant but different densities for jet spine and jet sheath. In this
paper, we look at the effects of radial stratification on jet integrity, mixing
between the different jet components and global morphology of the jet-head and
surrounding cocoon.
