Complexity reduction of collisional-radiative kinetics for atomic plasma

Abstract

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A new methodology for the reduction of vibrational kinetics in non-equilibrium microwave plasma: application to CO2 dissociation

“…For instance, in 28 closer to the one presented here; specifically, the kinetics are described by the vibrational and translational temperatures for the dissociation and recombination regimes of N 2 + N in nonequilibrium hypersonic flows. Approaches where internal modes of molecules are divided into several groups have been reported as well [24][25][26] . Such a multigroup lumping method was recently applied to reduce the vibrational kinetics of CO 2 38 .…”

“…As opposed to [24][25][26] , our approach is based on lumping all the asymmetric vibrational levels within a single group. In addition, a non-equilibrium distribution, the so-called Treanor distribution, is considered in the lumping process instead of the commonly used Boltzmann distribution.…”

“…Two different simplification techniques are coupled to carry out the reduction process: i) chemical lumping of species, where several species are grouped into a single pseudo-species, in combination with ii) a skeletal reduction approach, which includes identification and selection of the most influencing species in the dissociation process without loss of qualitative potential 1,19,23 . The novelty of the presented model lies in four key elements; 1) all the asymmetric vibrational levels are lumped within a single group instead of several groups as reported in [24][25][26] , 2) this group follows the non-equilibrium those at the outlet of the reactor. It is important to remark that the purpose of the work is to explore and validate a new methodology for the reduction of vibrational plasma kinetics, exemplified herein for a CO 2 non-thermal microwave discharge, rather than performing self-consistent multidimensional simulations, a task that has not been carried out yet.…”

Modeling of inelastic collisions in a multifluid plasma: Excitation and deexcitation

“…The required level of detail of the CR model is typically not known a priori and is possibly changing in a dynamical fashion as the system evolves in time. This can be resolved by coarse-graining techniques, which reduce the complexity of the kinetics to avoid solving a large system of equations [14][15][16] . The second issue comes from translational nonequilibrium, often found in a discharge, where we have both a bulk plasma (continuum) and a highly energetic component (kinetic), e.g., electrons emitted from the cathode.…”

An Approximate Time-Parallel Method for the Fast and Accurate Computation of Particle Trajectories in a Magnetic Field*

“…Such model pairs are many, and include fluid equations as an approximation to kinetic equations (such as the Vlasov equation) [1] [2] and complexity reduction techniques for collisional-radiative physics [3]. Construction of approximate solutions, such as these, has been done for eons for some types of problems and includes such approaches as a perturbation analysis of an equilibrium state.…”