  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 a nd 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 w ith scale heights of 500 pc and of 1 to 1.5 kpc,
respectively. The upper parts o f the thick HII disk (the diffuse ionized
medium) act as a disk-halo interface a nd its formation and stability are
directly correlated to the supernova rate per unit area in the simulated disk.
