  The driven transport of plastic systems in various disordered backgrounds is
studied within mean field theory. Plasticity is modeled using non-convex
interparticle potentials that allow for phase slips. This theory most naturally
describes sliding charge density waves; other applications include flow of
colloidal particles or driven magnetic flux vortices in disordered backgrounds.
The phase diagrams exhibit generic phases and phase boundaries, though the
shapes of the phase boundaries depend on the shape of the disorder potential.
The phases are distinguished by their velocity and coherence: the moving phase
generically has finite coherence, while pinned states can be coherent or
incoherent. The coherent and incoherent static phases can coexist in parameter
space, in contrast with previous results for exactly sinusoidal pinning
potentials. Transitions between the moving and static states can also be
hysteretic. The depinning transition from the static to sliding states can be
determined analytically, while the repinning transition from the moving to the
pinned phases is computed by direct simulation.
