Observations of particle motion in a complex plasma monolayer in rf discharge have revealed anomalous dependence on neutral gas pressure; an immobile system at high gas pressures, then, decreasing the pressure, a state with viscoelastic vortical fluid motions and, hence, dramatically enhanced transport, followed again by an ordered state. While the inhibited transport at higher pressures can be attributed to dissipation on neutrals, the transition of the system back to an ordered state at lower pressures has been explained by an increase of the dust-dust viscous dissipation due to significant modifications of the interaction potential between the particles.
2007. Vol. 14, no 1