Electron-ion three-body recombination coefficient of argon

Abstract

Spectroscopic measurements of a 15-kW flowing argon plasma, produced by an atmospheric pressure radio frequency inductively coupled plasma torch, have been made. The plasma is found to be in partial local thermodynamic equilibrium at electronic levels as low as 4p. Ionizational nonequilibrium is observed in the form of an elevated electron density due to the finite three-body electron-ion recombination rate. The flowing plasma is modeled using a two-dimensional axisymmetric flow code, incorporating partial local thermodynamic equilibrium effects, radiative transfer, and ionizational nonequilibrium through the coupled electron continuity equation