A new ionisation network and radiation transport module in PLUTO
  We introduce a new general-purpose time-dependent ionisation network (IN) and
a radiation transport (RT) module in the magneto-hydrodynamic (MHD) code PLUTO.
Our ionisation network is reliable for temperatures ranging from 5e3 to 3e8 K,
and includes all ionisation states of H, He, C, N, O, Ne, Mg, Si, S and Fe
making it suitable for studying a variety of astrophysical scenarios. Radiation
loss for each ion-electron pair is calculated using CLOUDY-17 data on-the-fly.
Photo-ionisation and charge exchange are the chemical heating mechanisms. The
IN is fully coupled to the radiation transport module over a very large range
of opacities at different frequencies. The RT module employs a method of short
characteristics assuming spherical symmetry. The radiation module requires the
assumption of spherical symmetry, while the IN is compatible with full 3D. We
also include a simple prescription for dust opacity, grain destruction, and the
dust contribution to radiation pressure. We present numerical tests to show the
reliability and limitations of the new modules. We also present a
post-processing tool to calculate projected column densities and emission
spectra.
