THE MODEL

We solve the MHD equations in three dimensions simulating the ISM at intermediate scale ($\sim 1$ kpc), including: a parameterization of the cooling laws appropriate for atomic and ionized gas, expressed as piecewise power laws of the temperature and the density (see Passot et al. 1995 for details); model terms for diffuse and stellar heating; the Coriolis force, and self-gravity. In this case, the x, y and zcoordinates respectively correspond to the azimuthal, radial and vertical directions in the Galactic disk. The resolution of this simulation is 128³.