Microscopic observation of confinement-induced layering and slow dynamics of dusty-plasma liquids in narrow channels

We report the microscopic observation of the confinement induced layering of quasi-2D dusty-plasma liquids in mesoscopic channels at a width W down to a few interparticle spacings. The two straight boundaries suppress nearby transverse hopping. It causes the formation of two to three layers with anisotropic diffusion nearby each boundary, and the randomly oriented bulklike liquid with isotropic diffusion in the center for a Wgreater than or equal to7 interlayer width. The pinching of the boundary layers from both sides leads to the transition to the layered structure with slow dynamics through the whole system as W decreases to five interlayer width. The packing and motion under an improper smaller W are also discussed.