Observations of high speed particle streams in dc glow discharge dusty plasmas

This paper reports on measurements of high speed flows of micron-sized particles in dc glow discharge dusty plasmas. In these experimental investigations, the dust particles are observed to flow towards the anode region in streams or channels with peak speeds of νst⩾30 mm/s. These speeds are 5 to 15 times faster than the average speed of the particles (νcl⩽2 mm/s) in the central dust cloud. Through the use of the particle image velocimetry measurement technique, the spatial distributions of particle velocities in these streams are directly measured. From these measurements, estimates of the spatial structure of the plasma potential in the vicinity of the dust cloud boundary are made.