Manipulating dust charge using ultraviolet light in a complex plasma

Making use of a 1-D particle-in-cell plus Monte Carlo code, which includes the scattering and collection of plasma particles on dust immersed in the plasma, we study the effect of photodetachment by ultraviolet (UV) photons in a radio frequency dusty argon plasma. This is done by adding a UV source in the model, which results in a UV flux entering the plasma from the left side. The dust charge is reduced for dust clouds consisting of 5-μm particles at a dust density relevant for both experiments and plasma applications. Using UV photons with energies above the work function, but below the ionization threshold, at fluxes of a few tens of watts per square meter, provides an interesting tool to control the dust charge in such plasmas. This could result in a way to control the dust particle coagulation or dust transport. For very high dust densities, the dust charge is not reduced by the incident UV photons.