in order to reproduce the observed ionization fraction, one would need to specify a distributed radiation source, but such feature is unfortunately not currently implemented in [Cloudy]{}.

The values of the model parameters can be tuned to better match the observed total density profiles and the molecular Hydrogen fraction. Blue solid lines in Figure \[figObs\] shows the results of a model where the mid-plane density is set to $n_0=0.75$ cm$^{-3}$, the intensity of the magnetic field is $B_0=4~\mu$G at the centre and varies with gas density as $(B/B_0) = (n/n_0)^{0.5}$, and the incident continuum has been propagated through a column density of $N({\rm H})=10^{22}$ cm$^{-2}$. Nevertheless, we strongly advise caution when interpreting these results. Although the fair agreement obtained for the atomic and molecular data provides encouraging support for the validity of our implementation of gravity, a more realistic model of the ISM is clearly required in order to derive robust quantitative constraints on its physical properties. Based on our crude model, we would simply argue that reasonable values of the input parameters (in particular, central gas density and magnetic field) yield reasonable scale heights for the disk. Atomic and molecular Hydrogen densities typically agree with observations within a factor 