Kinetic Monte Carlo simulations of plasma-chemistry

Abstract

This work presents a kinetic Monte Carlo algorithm to solve the gas-phase chemistry in low-temperature plasmas, as a first effort to achieve a unified formulation of the electron and heavy-particle kinetics based on Monte Carlo techniques. The implemented algorithm is successfully validated in the thermodynamic limit from the comparison with the traditional deterministic description using rate-balance equations. The accuracy of the Monte Carlo description of the rare species strongly depends on the number of particles used in the simulation. To surpass this limitation, two novel variance reduction techniques that significantly reduce the statistical fluctuations on the concentrations of the minor species are proposed and evaluated. These techniques lead to significant gains in computational time, up to factors of the order of 104 times in the cases studied, while ensuring the same quality of the solution.

Atmospheric pressure Townsend discharge in pure nitrogen—a test case for N2( A3Σu+,v ) kinetics under low E/N conditions

“…) in the equation (17). On the other side, the build-up of the N( 4 S) density from the model indicates that after a sufficient number of the AC cycles the quenching caused by the processes P1263 and P1264 should prevail over the pooling processes, which requires further experimental studies.…”

“…The minima of I HIR(2, 0) signals were normed to 1, and the fit (to obtain the decay constant τ A eff ) was performed in the y-value of 1.15 in order to be close to the signal minimum and ensure to be in the postdischarge phase. τ A eff obtained by the fit was used to calculate the metastable density using the equation (17). Such procedure leads to metastable densities 1.9 •10 12 , 1.0 •10 13 , and 2.5 •10 13 cm −3 for 12, 13, and 14 kV, respectively.…”

“…Such procedure leads to metastable densities 1.9 •10 12 , 1.0 •10 13 , and 2.5 •10 13 cm −3 for 12, 13, and 14 kV, respectively. In the equation (17), the rate constants of [45,48], defined as: k pool = 8.0 • 10 −10 cm 3 s −1 and k q = 3.4 • 10 −16 cm 3 s −1 , were used. The value k pool = 8.0 • 10 −10 cm 3 s −1 was obtained from pooling reactions:…”

“…The authors used the method of optical-optical double resonance-LIF (OODR-LIF) to evaluate concentrations of N 2 (A 3 Σ + u , v = 0) level in pure nitrogen and nitrogen with small admixtures of oxygen in a 1.4 mm DBD gap (AC HV 11 kV p-p at 1.79 kHz) and reported peak values of approximately 1.5 ×10 13 cm −3 . Last but not least, owing to the great complexity of the collisional and energy transfer processes in molecular nitrogen under nonequilibrium discharge conditions [16][17][18] the role of N 2 (A 3 Σ + u , v) species in the APTD mechanism has so far been evaluated using numerical models based on very simplified kinetic schemes.…”

Plasma-assisted agriculture: history, presence, and prospects—a review

“…Processes occurring in low-temperature nonequilibrium plasmas are determined by extremely complex kinetics [177][178][179] occurring in nitrogen-oxygen mixtures under atmospheric pressure. The importance and impact of these species depend on their kinetic energy, reactivity, and diffusion as well as their extent of interaction with solid materials.…”