Local Turbulence Simulations for the Multiphase ISM
  In this paper we show results of numerical simulations for the turbulence in
the interstellar medium. These results were obtained using a Riemann
solver-free numerical scheme for high-Mach number hyperbolic equations. Here we
especially concentrate on the physical properties of the ISM. That is, we do
not present turbulence simulations trimmed to be applicable to the interstellar
medium. The simulations are rather based on physical estimates for the relevant
parameters of the interstellar gas.
  Applying our code to simulate the turbulent plasma motion within a typical
interstellar molecular cloud, we investigate the influence of different
equations of state (isothermal and adiabatic) on the statistical properties of
the resulting turbulent structures. We find slightly different density power
spectra and dispersion maps, while both cases yield qualitatively similar
dissipative structures, and exhibit a departure from the classical Kolmogorov
case towards a scaling described by the She-Leveque model.
  Solving the full energy equation with realistic heating/cooling terms
appropriate for the diffuse interstellar gas, we are able to reproduce a
realistic two-phase distribution of cold and warm plasma. When extracting maps
of polarised intensity from our simulation data, we find encouraging similarity
to actual observations. Finally, we compare the actual magnetic field strength
of our simulations to its value inferred from the rotation measure. We find
these to be systematically different by a factor of about 1.5, thus
highlighting the often underestimated influence of varying line-of-sight
particle densities on the magnetic field strength derived from observed
rotation measures.
