  We investigate the coupling between the temporal variation from
galaxy-formation feedback and the bar instability. We show that fluctuations
from mass outflow on star-formation time scales affect the radial motion of
disk orbits. The resulting incoherence in orbital phase leads to the disruption
of the bar-forming dynamics. Bar formation is suppressed in starburst galaxies
that have fluctuation time scales within the range 10 Myr to 200 Myr with
repeated events with wind mass 15% of the disk within 0.5 scale lengths or 1.4%
of the total disk mass. The work done by feedback is capable of reducing the
amplitude or, with enough amplitude, destroying an existing bar. AGN feedback
with similar amplitude and timescales would have similar behavior. To model the
dynamics of the coupling and interpret the results of the full N-body
simulations, we introduce a generalization of the Hamiltonian mean-field (HMF)
model, drawing inspiration from the Lynden-Bell (1979) mechanism for bar
growth. Our non-linear 'BarHMF' model is designed to reproduce linear
perturbation theory in the low-amplitude limit. Notably, without star-formation
feedback, this model exhibits exponential growth whose rate depends on disk
mass and reproduces the expected saturation of bar growth observed in N-body
simulations. We describe several promising applications of the BarHMF model
beyond this study.
