Two-dimensional pulsed-plasma simulation of a chlorine discharge

Abstract

A two-dimensional (r,z) continuum model was developed to study the spatiotemporal dynamics of a pulsed power (square-wave modulated) chlorine discharge sustained in an inductively coupled plasma (ICP) reactor with a planar coil. The self-consistent model included Maxwell’s equations for the power deposition profiles coupled to the electron energy equation and the species mass balances. Simulation results showed separation of the plasma into an electronegative core and an electropositive edge during the active glow (power on) and the formation of an ion–ion plasma ∼15 μs into the afterglow (power off). During the early active glow, the negative ion flux was convection dominated near the quartz window of the ICP reactor due to the formation of large electrostatic fields, leading to a self-sharpening front propagating into the plasma. The negative ion density profiles were found to have a strong spatial dependence underlying the importance of spatial resolution in negative ion density measurements. The time dependent ion and radical flux uniformity was also studied. Simulation results were compared with experimental data and reasonable agreement was observed.