Charged macroparticles over liquid helium

An analysis of properties of a plasma with macroparticles (dust plasma) at cryogenic temperatures led us to the need to account for the effects of helium condensation on these particles. Micrometer particles in the saturated helium vapor are coated with a film of liquid helium with the thickness of about 100 Å. This limits their electronic charge, since the helium film is weakly permeable to electrons. The exceptions are clusters of Cs, Rb and K, which are not wetted by helium.