Electronic-state-resolved non-equilibrium analysis of ICP discharges

The present work focuses on the study of non-equilibrium effects in radio frequency inductively coupled plasmas (ICP) using state-of-the-art electronic State-to-State (StS) model. A multi-physics computational framework has been developed to simulate the magnetohydrodynamics (MHD) phenomena inside ICPs. The fluid governing equations are discretized in space based on a cell-centered finite volume method. A preconditioned compressible formulation is adopted to tackle the stiffness resulting from low Mach numbers. Non-local thermodynamic equilibrium (NLTE) calculations are performed using either multi-temperature or State-to-State models. Electromagnetic equations are solved via a mixed finite element method. Two solvers, one for the fluid and the other for the electromagnetic phenomena, are coupled in an explicit fashion to model NLTE ICP discharges. Calculations performed using a two-temperature NLTE model highlight the importance of non-equilibrium modeling in the torch. Further, simulations performed using an electronic State-to-State model show significant deviations of the population of high-lying states from local equilibrium (e.g., Boltzmann distribution).