Dependence of the Dust-Particle Charge on Its Size in a Glow-Discharge Plasma

Abstract

Measurements of the charge of dust grains have been performed in a quasineutral plasma over a wide range of grain sizes. A new method was established for measuring the charge on grains levitating in the striations of a dc glow discharge. A single dust particle is moved out of a dust cloud with the help of a focused laser beam. When it leaves the beam it returns back to the cloud, and the charge on the grain is derived from the analysis of the returning trajectory. The obtained dependence of the dust-grain charge on its size was found to be strongly nonlinear in the experimental conditions.