The disk-halo interaction: superbubbles and the structure of the interstellar medium

A chimney model for the Galaxy is presented and its underlying physical principles are explained. The crucial point of the model is that the Galactic disk and halo are connected by chimneys which are a consequence of superbubbles bursting out of the disk forming these collimated structures through which the global mass and energy exchange flows from disk to halo. For canonical Galaxy parameters, the chimney phase is found to be associated with a mass flow rate of 0.3-3 solar masses/yr and a global power input of 10 to the 40th to 10 to the 42nd ergs/s. 72 refs.