Effect of negatively biased electrode on two ion species plasma–wall transition, ion drag force, and levitation of dust particle

Abstract

The effect of negatively biased electrodes on two ion species (argon and xenon) magnetized plasma–wall transition characteristics and the levitation of an isolated dust particle in the sheath region has been investigated using the kinetic trajectory simulation method based on a kinetic theory. It is found that the electrode biasing affects the transition parameters: space charge density, sheath potential, evolution of phase-space, and particle flux toward the electrode. The scale length of the Debye sheath region becomes widened for the increase in negative biasing and the presence of magnetic field as well. The biasing voltage and size of the dust particle have significant effect on the evolution of the dust charge, ion drag force, and levitation of a charged dust grain in the transition region. The dust particle is negatively charged at the particle injection side, and it acquires a positive charge for higher biasing voltage close to the electrode owing to electron depletion in that region. The distance of stable levitation from the electrode increases with the increase in the negative voltage applied to the electrode. Furthermore, the volumetric composition of two species of positive ions influence the dust charging process with the negative charge of the dust particle increasing as the concentration of xenon ions increases.