Charging and Mobilization of Dust Particles on a Surface in Plasma

We present first experimental results showing that single dust particles on a dielectric surface are mobilized and lofted due to exposure to an electron beam or ultraviolet radiation. It is shown that secondary electrons and/or photoelectrons emitted from a substrate surface are recollected on the surfaces within microcavities between a dust particle and the substrate surface, resulting in large negative charges and subsequently causing mobilization of the dust particle due to Coulomb repulsion. Dust mobility tested against the electron beam energy is shown to follow the secondary electron yield curve of the substrate surface in both the experimental and modeling results. The results verified the role of emitted electrons from the substrate surface in charging and mobilization of single dust particles.