Global plasma simulations using dynamically generated chemical models

Abstract

Extensive molecular data are a key requirement in understanding modern technical plasmas. A method for coupling molecular data with chemical models in a global plasma simulation to enable rapid testing and evaluation of new plasmas is presented. A global plasma model (GLOBALKIN) is extended using an expert system (Quantemol-P) to enable ad hoc simulations using new plasma recipes. A set of atomic and molecular species to be considered in the plasma simulation is specified by the user. The expert system generates a complete set of reaction pathways for both the gas and surface reactions in a plasma. This set is pruned by discarding unphysical reactions and reaction data not appropriate to technical plasmas (such as autodetachment). The species, gas phase reactions, surface reactions, and plasma properties can be adjusted to control the simulation. The reaction list is populated through a database of molecular parameters and cross sections; missing data can be calculated through molecular cross sections using a further expert system (Quantemol-N) which applies the R-matrix method to electron-molecule collisions. For cases where the R-matrix method is not appropriate, other methods are used to maximize the range of cross-section data available. The Quantemol-P expert system allows rapid creation of new plasma recipes and investigation of their effects allowing a greater level of flexibility than previously achievable.