High Resolution Simulations of the Global and Local ISM

We present the first to date high resolution calculations of the ISM down to scales of 0.625 pc of the global and local ISM. The simulations show the morphology and structure of the different ISM phases and reproduce many of the features that have been observed in the Milky Way and other galaxies. In particular, they show that the hot gas has a moderately low volume filling factor (∼ 20%) even in the absence of magnetic fields. Also, cold gas is mainly concentrated in filamentary structures running perpendicular to the midplane forming and dissipating within ∼ 10− 12 Myr. Compression is the dominant process for their formation, but thermal instability also plays a rôle. Also the evolution of the Local Bubble is simulated by multi-supernova explosions; calculated extensions after ∼ 13 Myr match observations.