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We develop a stochastic model for the charge fluctuations on a microscopic dust particle resting on a surface exposed to plasma. We find in steady state that the fluctuations are normally distributed with a standard deviation that is proportional to $CT_{e})^{1/2}$, where $C$ is the particle-surface capacitance and $T_{e}$ is the plasma electron temperature. The time for an initially uncharged ensemble of particles to reach the steady state distribution is directly proportional to $CT_{e}$.
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A nanometer-sized dielectric particle lying on a dielectric substrate is exposed to the flux of low-energy electrons, ion and electron fluxes from a cold plasma and the fluxes from the combination of these two sources with the help of particle-in-cell simulation to investigate the particle lofting phenomenon. The results are of interest for dust mitigation in the semiconductor industry, the lunar exploration, and the explanation of the dust levitation.
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