The challenges of modelling microphysics: ambipolar diffusion,
  chemistry, and cosmic rays in MHD shocks
  From molecular clouds to protoplanetary disks, non-ideal magnetic effects are
important in many astrophysical environments. Indeed, in star and disk
formation processes, it has become clear that these effects are critical to the
evolution of the system. The efficacy of non-ideal effects are, however,
determined by the complex interplay between magnetic fields, ionising
radiation, cosmic rays, microphysics, and chemistry. In order to understand
these key microphysical parameters, we present a one-dimensional non-ideal
magnetohydrodynamics code and apply it to a model of a time-dependent, oblique,
magnetic shock wave. By varying the microphysical ingredients of the model, we
find that cosmic rays and dust play a major role, and that, despite the
uncertainties, the inclusion of microphysics is essential to obtain a realistic
outcome in magnetic astrophysical simulations.
