  The behavior of particles driven through a narrow constriction is
investigated in experiment and simulation. The system of particles adapts to
the confining potentials and the interaction energies by a self-consistent
arrangement of the particles. It results in the formation of layers throughout
the channel and of a density gradient along the channel. The particles
accommodate to the density gradient by reducing the number of layers one by one
when it is energetically favorable. The position of the layer reduction zone
fluctuates with time while the particles continuously pass this zone. The flow
behavior of the particles is studied in detail. The velocities of the particles
and their diffusion behavior reflect the influence of the self-organized order
of the system.
