Multicomponent transport in plasmas; exploiting stoichiometry

A system of mass balance equations is set up for plasma-chemical simulations, we derive the diffusion velocities from Stefan-Maxwell theory. An algorithm to linearly transform the system of mass balance equations in the context of non-LTE plasmas is described. This transformation is derived from the reaction set, and eliminates part of the chemical source term, enforces invariants such as conservation of mass and quasi neutrality up to machine precision, provides a reduction in the number of unknowns, and significantly improves conditioning of the discretized system. The MATLAB code used in the numerical experiments is available on GitLab: https://gitlab.com/ChrisSchoutrop/stoichiometric-transformation. (c) 2020 The Authors. Published by Elsevier Inc.