Disk-Halo Interaction - I. Three-Dimensional Evolution of the Galactic Disk

The results of a three-dimensional model for disk-halo interaction are presented here. The model considers explicitly the input of energy and mass by isolated and correlated supernovae in the disk. Once disrupted by the explosions, the disk never returns to its initial state. Instead it approaches a state where a thin HI disk is formed in the Galactic plane overlayed by thick HI and HII gas disk with scale heights of 500 pc and of 1 to 1.5 kpc, respectively. The upper parts of the thick HII disk (the diffuse ionized medium) act as a disk-halo interface and its formation and stability are directly correlated to the supernova rate per unit area in the simulated disk.