Photo-discharging: A path towards controlling dust in low-temperature plasmas*

Charged microparticles (dust) suspended in low-temperature plasmas represent a tool for researchers and an unwanted contaminant for practical plasmas; the lack of independent control over the equilibrium charge of the dust particles is a significant obstacle to improving dust confinement or removal. A recent proof-of-concept test on the Auburn Dusty Plasma Experiment (DPX) combining Lanthanum Boride (LaB6) particles with a high-intensity UV source have demonstrated that photoelectric currents can significantly alter the equilibrium properties of dust; and that by tailoring the properties of the light source to the material properties of the dust and the apparatus, this control may be accomplished with minimal perturbation to the background plasma. Probe measurements of the background plasma and video analysis of the dust particles' response to the UV are presented. The potential of applying photo-discharging in research and practical plasmas is discussed.