Glow Discharge in a High-Velocity Air Flow: The Role of the Associative Ionization Reactions Involving Excited Atoms

A kinetic scheme for non-equilibrium regimes of atmospheric pressure air discharges is developed. A distinctive feature of this model is that it includes associative ionization with the participation of N(2D, 2P) atoms. The thermal dissociation of vibrationally excited nitrogen molecules and the electronic excitation from all the vibrational levels of the nitrogen molecules are also accounted for. The model is used to simulate the parameters of a glow discharge ignited in a fast longitudinal flow of preheated (T0 = 1800–2900 K) air. The results adequately describe the dependence of the electric field in the glow discharge on the initial gas temperature. For T0 = 1800 K, a substantial acceleration in the ionization kinetics of the discharge is found at current densities larger than 3 A/cm2, mainly due to the N(2P) + O(3P) → NO+ + e process; being the N(2P) atoms produced via quenching of N2(A3∑u+) molecules by N(4S) atoms. Correspondingly, the reduced electric field noticeably falls because the electron energy (6.2 eV) required for the excitation of the N2(A3∑u+) state is considerably lower than the ionization energy (9.27 eV) of the NO molecules. For higher values of T0, the associative ionization N(2D) + O(3P) → NO+ + e process (with a low–activation barrier of 0.38 eV) becomes also important in the production of charged particles. The N(2D) atoms being mainly produced via quenching of N2(A3∑u+) molecules by O(3P) atoms.

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Modelling of an Atmospheric–Pressure Air Glow Discharge Operating in High–Gas Temperature Regimes: The Role of the Associative Ionization Reactions Involving Excited Atoms

Plasma ◽

10.3390/plasma3010003 ◽

2020 ◽

Vol 3 (1) ◽

pp. 12-26

Author(s):

Ezequiel Cejas ◽

Beatriz Mancinelli ◽

Leandro Prevosto

Keyword(s):

Atmospheric Pressure ◽

Vibrational Excitation ◽

Thermal Dissociation ◽

Ionization Mechanism ◽

Gas Temperature ◽

Excited Atoms ◽

Temperature Regimes ◽

Ionization Reaction ◽

Associative Ionization

A model of a stationary glow-type discharge in atmospheric-pressure air operated in high-gas-temperature regimes (1000 K < Tg < 6000 K), with a focus on the role of associative ionization reactions involving N(2D,2P)-excited atoms, is developed. Thermal dissociation of vibrationally excited nitrogen molecules, as well as electronic excitation from all the vibrational levels of the nitrogen molecules, is also accounted for. The calculations show that the near-threshold associative ionization reaction, N(2D) + O(3P) → NO+ + e, is the major ionization mechanism in air at 2500 K < Tg < 4500 K while the ionization of NO molecules by electron impact is the dominant mechanism at lower gas temperatures and the high-threshold associative ionization reaction involving ground-state atoms dominates at higher temperatures. The exoergic associative ionization reaction, N(2P) + O(3P) → NO+ + e, also speeds up the ionization at the highest temperature values. The vibrational excitation of the gas significantly accelerates the production of N2(A3∑u+) molecules, which in turn increases the densities of excited N(2D,2P) atoms. Because the electron energy required for the excitation of the N2(A3∑u+) state from N2(X1∑g+, v) molecules (e.g., 6.2 eV for v = 0) is considerably lower than the ionization energy (9.27 eV) of the NO molecules, the reduced electric field begins to noticeably fall at Tg > 2500 K. The calculated plasma parameters agree with the available experimental data.

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Mechanisms of the electron density depletion in the SAR arc region

Annales Geophysicae ◽

10.1007/s00585-996-0211-7 ◽

1996 ◽

Vol 14 (2) ◽

pp. 211-221 ◽

Cited By ~ 15

Author(s):

A. V. Pavlov

Keyword(s):

Electric Field ◽

Magnetic Storm ◽

Electron Density ◽

Drift Velocity ◽

Recovery Phase ◽

Electron Densities ◽

Model Framework ◽

Vibrationally Excited ◽

Plasma Drift ◽

Excited Nitrogen

Abstract. This study compares the measurements of electron density and temperature and the integral airglow intensity at 630 nm in the SAR arc region and slightly south of this (obtained by the Isis 2 spacecraft during the 18 December 1971 magnetic storm), with the model results obtained using the time dependent one-dimensional mathematical model of the Earth\\'s ionosphere and plasmasphere. The explicit expression in the third Enskog approximation for the electron thermal conductivity coefficient in the multicomponent mixture of ionized gases and a simplified calculation method for this coefficient presents an opportunity to calculate more exactly the electron temperature and density and 630 nm emission within SAR arc region are used in the model. Collisions between N2 and hot thermal electrons in the SAR arc region produce vibrationally excited nitrogen molecules. It appears that the loss rate of O+(4S) due to reactions with the vibrationally excited nitrogen is enough to explain electron density depression by a factor of two at F-region heights and the topside ionosphere density variations within the SAR arc if the erosion of plasma within geomagnetic field tubes, during the main phase of the geomagnetic storm and subsequent filling of geomagnetic tubes during the recovery phase, are considered. To explain the disagreement by a factor 1.5 between the observed and modeled SAR arc electron densities an additional plasma drift velocity ~–30 m s–1 in the ion continuity equations is needed during the recovery phase. This additional plasma drift velocity is likely caused by the transition from convecting to corotating flux tubes on the equatorward wall of the trough. The electron densities and temperatures and 630 nm integral intensity at the SAR arc and slightly south of this region as measured for the 18 December 1971 magnetic storm were correctly described by the model without perpendicular electric fields. Within this model framework the effect of the perpendicular electric field ~100 mv m–1 with a duration ~1 h on the SAR arc electron density profiles was found to be large. However, this effect is small if ~1–2 h have passed after the electric field was set equal to zero.

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Effect of the electric field in glow discharge plasma sheath on the optoelectronic properties of the AlxZn1-xO thin films

Optik ◽

10.1016/j.ijleo.2021.166772 ◽

2021 ◽

Vol 239 ◽

pp. 166772

Author(s):

A. Amini ◽

M.S. Zakerhamidi ◽

S. Khorram

Keyword(s):

Thin Films ◽

Glow Discharge ◽

Electric Field ◽

Discharge Plasma ◽

Optoelectronic Properties ◽

Plasma Sheath ◽

Glow Discharge Plasma

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Semi-analytical investigation on plasma density and reduced electric field of glow discharge in a turnery gas cw-CO2 laser

Optik ◽

10.1016/j.ijleo.2021.166592 ◽

2021 ◽

pp. 166592

Author(s):

Nader Morshedian ◽

Mojtaba Kabir ◽

Majid Aram ◽

Ahmad Mehramiz

Keyword(s):

Glow Discharge ◽

Electric Field ◽

Plasma Density ◽

Co2 Laser ◽

Analytical Investigation ◽

Cw Co2 Laser

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Electric field distribution in the cathode sheath of an electron beam glow discharge

Applied Physics Letters ◽

10.1063/1.98405 ◽

1987 ◽

Vol 51 (6) ◽

pp. 409-411 ◽

Cited By ~ 17

Author(s):

S. A. Lee ◽

L.‐U. A. Andersen ◽

J. J. Rocca ◽

M. Marconi ◽

N. D. Reesor

Keyword(s):

Electron Beam ◽

Glow Discharge ◽

Electric Field ◽

Field Distribution ◽

Electric Field Distribution ◽

Cathode Sheath

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The role of vibrationally excited oxygen and nitrogen in the ionosphere during the undisturbed and geomagnetic storm period of 6-12 April 1990

Annales Geophysicae ◽

10.1007/s00585-998-0589-5 ◽

1998 ◽

Vol 16 (5) ◽

pp. 589-601 ◽

Cited By ~ 33

Author(s):

A. V. Pavlov

Keyword(s):

Loss Rate ◽

Boltzmann Distribution ◽

Rate Coefficients ◽

Ion Chemistry ◽

Vibrationally Excited ◽

Model Calculations ◽

F Region ◽

Neutral Temperature ◽

The Difference ◽

Excited Nitrogen

Abstract. We present a comparison of the observed behavior of the F-region ionosphere over Millstone Hill during the geomagnetically quiet and storm periods of 6–12 April 1990 with numerical model calculations from the IZMIRAN time-dependent mathematical model of the Earth's ionosphere and plasmasphere. The major enhancement to the IZMIRAN model developed in this study is the use of a new loss rate of O+(4S) ions as a result of new high-temperature flowing afterglow measurements of the rate coefficients K1 and K2 for the reactions of O+(4S) with N2 and O2. The deviations from the Boltzmann distribution for the first five vibrational levels of O2(v) were calculated, and the present study suggests that these deviations are not significant. It was found that the difference between the non-Boltzmann and Boltzmann distribution assumptions of O2(v) and the difference between ion and neutral temperature can lead to an increase of up to about 3 or a decrease of up to about 4 of the calculated NmF2 as a result of a respective increase or a decrease in K2. The IZMIRAN model reproduces major features of the data. We found that the inclusion of vibrationally excited N2(v > 0) and O2(v > 0) in the calculations improves the agreement between the calculated NmF2 and the data on 6, 9, and 10 April. However, both the daytime and nighttime densities are reproduced by the IZMIRAN model without the vibrationally excited nitrogen and oxygen on 8 and 11 April better than the IZMIRAN model with N2(v > 0) and O2(v > 0). This could be due to possible uncertainties in model neutral temperature and densities, EUV fluxes, rate coefficients, and the flow of ionization between the ionosphere and plasmasphere, and possible horizontal divergence of the flux of ionization above the station. Our calculations show that the increase in the O+ + N2 rate factor due to N2(v > 0) produces a 5-36 decrease in the calculated daytime peak density. The increase in the O++ O2 loss rate due to vibrational-ly excited O2 produces 8-46 reductions in NmF2. The effects of vibrationally excited O2 and N2 on Ne and Te are most pronounced during the daytime.Key words. Ion chemistry and composition · Ionosphere – atmosphere interactions · Ionospheric disturbances

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