  Star formation is self-regulated by its feedback that drives turbulence and
heats the gas. In equilibrium, the star formation rate (SFR) should be directly
related to the total (thermal plus turbulent) midplane pressure and hence the
total weight of the diffuse gas if energy balance and vertical dynamical
equilibrium hold simultaneously. To investigate this quantitatively, we utilize
numerical hydrodynamic simulations focused on outer-disk regions where diffuse
atomic gas dominates. By analyzing gas properties at saturation, we obtain
relationships between the turbulence driving and dissipation rates, heating and
cooling rates, the total midplane pressure and the total weight of gas, and the
SFR and the total midplane pressure. We find a nearly linear relationship
between the SFR and the midplane pressure consistent with the theoretical
prediction.
