Dust particle dynamics in low-pressure plasma reactor

Abstract

In this paper, the structure of a rf plasma glow discharge in a parallel-plate geometry is revisited through a numerical solution of the well-known local field approximation model equations. The dynamics of a dust particle injected into the plasma is elaborated in a Lagrangian framework by solving the particle equations for its motion and charge. Different ion drag expressions are considered. For particles of three different sizes, magnitudes of various forces such as gravity, electricity, and ion drag acting on a stationary particle are compared to each other. Particle potential energy, together with its possible wells, is demonstrated for each case. Taking into account the neutral drag force, damping oscillations and final locations of the particles, depending on their initial injection position (top or bottom), are captured. The transient characteristic of the charging process of smaller particles with respect to their motion time scale is discussed. The effect of inclusion of ion thermal energy in the calculation of drag force on the motion of the particle is illustrated.