Jets are observed to stir up multi-phase turbulence in the inter-stellar
medium as well as far beyond the host galaxy. Here we present detailed
simulations of this process. We evolve the hydrodynamics equations with
optically thin cooling for a 3D Kelvin Helmholtz setup with one initial cold
cloud. The cloud is quickly disrupted, but the fragments remain cold and are
spread throughout our simulation box. A scale free isotropic Kolmogorov power
spectrum is built up first on the large scales, and reaches almost down to the
grid scale after the simulation time of ten million years. We find a pronounced
peak in the temperature distribution at 14,000K. The luminosity of the gas in
this peak is correlated with the energy. We interpret this as a realisation of
the shock ionisation scenario. The interplay between shock heating and
radiative cooling establishes the equilibrium temperature. This is close to the
observed emission in some Narrow Line Regions. We also confirm the shift of the
phase equilibrium, i.e. a lower (higher) level of turbulence produces a higher
(lower) abundance of cold gas. The effect could plausibly lead to a high level
of cold gas condensation in the cocoons of extragalactic jets, explaining the
so called Alignment Effect.Comment: 4 pages, 3 figures, conference: "The central kpc", Crete, June 2008,
Volume 79 of the Memorie della Societa Astronomica Italian
