Decay instability of vibrational relaxation in molecular gases

Novobrantsev, I. V.; Starostin, A. N.

doi:10.1007/bf00850675

Cited by 3 publications

(2 citation statements)

References 1 publication

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“…The development of model 1, i.e. the consideration of other vibrational modes of CO 2 , could increase the importance of PVM mechanisms even though the interaction of these modes with the asymmetric one could decrease the spread of the asymmetric quanta on the high lying levels (see for example [61,62]).…”

Section: Perspectivesmentioning

confidence: 99%

Self-consistent time dependent vibrational and free electron kinetics for CO₂dissociation and ionization in cold plasmas

Capitelli

Colonna

D’Ammando

et al. 2017

Plasma Sources Sci. Technol.

109

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A self-consistent time dependent model, based on the coupling between the Boltzmann equation for free electrons, the non equilibrium vibrational kinetics for the asymmetric mode of CO 2 and simplified global models for the dissociation and ionization plasma chemistry, has been applied to conditions which can be met under pulsed microwave (MW), dielectric barrier discharge (DBD) and nanosecond pulsed discharges (NPD). Under MW discharge type conditions, the selected pulse duration generates large concentration of vibrational excited states, which affects the electron energy distribution function (eedf) through the superelastic vibrational collisions. Moreover, in discharge conditions, plateaux appear in the vibrational distribution function (vdf) through the vibrational-vibrational up pumping mechanism, persisting also in the post discharge. In post discharge conditions, also the eedf is characterized by plateaux due to the superelastic collisions between cold electrons and the CO 2 electronic state at 10.5 eV. The plateau in vdf increases the dissociation of pure vibrational mechanism (PVM), which can become competitive with the dissociation mechanism induced by electron molecule collisions. The PVM rates increase with the decrease of gas temperature, generating a non-Arrhenius behaviour. The situation completely changes under DBD and NPD type conditions characterized by shorter pulse duration and higher applied E/N values. Under discharge conditions, both vdf and eedf plateaux disappear, reappering in the afterglow.

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Section: Perspectivesmentioning

confidence: 99%

Self-consistent time dependent vibrational and free electron kinetics for CO₂dissociation and ionization in cold plasmas

Capitelli

Colonna

D’Ammando

et al. 2017

Plasma Sources Sci. Technol.

109

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“…Their population is thus comparable to the ground state population, which explains the high sensitivity of their temperatures to the uncertainties of the rate A c c e p t e d M a n u s c r i p t coefficients. At this high level of symmetric excitation, inter-mode energy exchanges can become important [45]. These non-linear effects are partly included in the model for the low-energy levels through reaction V5 (see Appendix A), but not for the higher energy levels, as this would lead to a complexity that is beyond this study.…”

Section: Quantification Of the Uncertainty On The Plasma Variablesmentioning

confidence: 99%

Modeling of CO₂plasma: effect of uncertainties in the plasma chemistry

Berthelot

Bogaerts

2017

Plasma Sources Sci. Technol.

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Low-temperature plasma chemical kinetic models are particularly important to the plasma community. These models typically require dozens of inputs, especially rate coefficients. The latter are not always precisely known and it is not surprising that the error on the rate coefficient data can propagate to the model output. In this paper, we present a model that uses N=400 different combinations of rate coefficients based on the uncertainty attributed to each rate coefficient, giving a good estimation of the uncertainty on the model output due to the rate coefficients. We demonstrate that the uncertainty varies a lot with the conditions and the type of output. Relatively low uncertainties (about 15 %) are found for electron density and temperature, while the uncertainty can reach more than an order of magnitude for the population of the vibrational levels in some cases and it can rise up to 100 % for the CO 2 conversion. The reactions that are mostly responsible for the largest uncertainties are identified. We show that the conditions of pressure, gas temperature and power density have a great effect on the uncertainty and on which reactions lead to this uncertainty. In all the cases tested here, while the absolute values may suffer from large uncertainties, the trends observed in previous modeling work are still valid. Finally, in accordance with the work of Turner, a number of "good practices" is recommended.

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Theoretical study of output parameters of high-pressure CO2 lasers with selective optical pumping in 4.3 ?m band

Trushin¹,

Churakov²

1981

J Appl Spectrosc

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Decay instability of vibrational relaxation in molecular gases

Cited by 3 publications

References 1 publication

Self-consistent time dependent vibrational and free electron kinetics for CO₂dissociation and ionization in cold plasmas

Self-consistent time dependent vibrational and free electron kinetics for CO₂dissociation and ionization in cold plasmas

Modeling of CO₂plasma: effect of uncertainties in the plasma chemistry

Theoretical study of output parameters of high-pressure CO2 lasers with selective optical pumping in 4.3 ?m band

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Decay instability of vibrational relaxation in molecular gases

Cited by 3 publications

References 1 publication

Self-consistent time dependent vibrational and free electron kinetics for CO2dissociation and ionization in cold plasmas

Self-consistent time dependent vibrational and free electron kinetics for CO2dissociation and ionization in cold plasmas

Modeling of CO2plasma: effect of uncertainties in the plasma chemistry

Theoretical study of output parameters of high-pressure CO2 lasers with selective optical pumping in 4.3 ?m band

Contact Info

Product

Resources

About

Self-consistent time dependent vibrational and free electron kinetics for CO₂dissociation and ionization in cold plasmas

Self-consistent time dependent vibrational and free electron kinetics for CO₂dissociation and ionization in cold plasmas

Modeling of CO₂plasma: effect of uncertainties in the plasma chemistry