Stereoscopic particle image velocimetry studies of transport in dusty plasmas

Over the past six years, the Auburn Plasma Sciences Laboratory (PSL) has been applying particle image velocimetry (PIV) techniques to the study of microparticle transport in dusty plasmas. PIV is a powerful experimental tool - originally developed in the fluid physics community - in which displacement of micron-sized particles is determined by two successive illuminations by a planar laser sheet. Since the time interval between the illuminations is a known quantity (i.e., set by the experimenter), the velocity of the particles can be computed. In a fluid, this measurement gives an indication of the collective motion of the medium. By contrast, in a dusty plasma, the PIV technique gives a direct measurement of the microparticle transport in the plasma. Furthermore, because the PIV technique is a measurement over a region, not just a point measurement, it can provide a global perspective on transport over the entire dusty plasma. In this manner, PIV provides a tool to study global plasma transport phenomena at a kinetic level. This presentation will briefly compare stereo-PIV to two-dimensional PIV and other optical dusty plasma diagnostics. The presentation will then highlight three unique capabilities of the stereo-PIV diagnostic: measuring three-dimensional particle transport, obtaining information on the three- dimensional velocity space distribution function, and reconstructing particle motion near dust acoustic waves.