Controlling the charge on dust particles using UV photo discharging

Dusty plasma is a four-component plasma consisting of electrons, ions, neutral gas, and microparticles (dust) which collect charge from the surrounding plasma environment. Controlling the charge on the dust particles has both academic and industrial applications. Previous research at Auburn University have shown that the charge on lanthanum hexaboride (LaB6) dust grains, suspended in a DC plasma, can be changed when exposed to an external UV source. However, due to the extremely asymmetric shapes and large size distribution of the LaB6 particles, the motion of some of the particles were stochastic and not fully under control. Hence, a new experiment, with both DC and RF plasma sources, is designed to broaden the former research by looking at different dust particles, such as melamine formaldehyde (MF) which have more uniform shape and size distributions. We shall show results from both MF and LaB6 particles, tested in both DC and RF generated plasmas over a large range of plasma source parameters such as input power and neutral gas pressure. In future, we also hope to study the effects of external magnetic field on this phenomenon.