Galaxies Method: numerical methods: numerical Charge transfer Convergence of numerical methods Cosmology Dynamo mechanism Galaxies: magnetic fields Galaxies: spirals Galaxy formations H ii region H ii regions Hydrodynamics ISM: abundance ISM: abundances Interactive devices Ionization of gases Ionization state Lagrange multipliers MHD Magnetic energies Magnetic-field Magnetohydrodynamics Metal cooling Metal line Metals Metals chemistry Non equilibrium Numerical methods Photoionization