Control of Ion Drag in a Dusty Plasma

A method of the control of the ion drag force acting on a dust particle in a complex plasma by choosing the composition of the gas mixture of a discharge has been proposed and experimentally implemented. The addition of a heavier additive with a lower ionization potential to the light buffer gas changes the ion composition and velocity of the ion flow. As a result, the ion drag force changes significantly. The experiments have been performed with the discharge in a helium-xenon mixture in a magnetic field. The measured angular rotation velocity of the dusty structure is in agreement with the numerical estimate of the ion drag force varying ( increasing) in the presence of small (<5%) xenon additive. The proposed method can be used to create plasma crystals with new properties.