&lt;title&gt;Continuous wave 200kW supersonic CO laser&lt;/title&gt;

Dymshits, B. M.; Ivanov, G. R.; Mescherskiy, A. N.; Kovsh, Ivan B

doi:10.1117/12.184632

Cited by 12 publications

(3 citation statements)

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“…This approach has been used in the past, e.g. in high-power CO 2 [2] and CO [3] lasers, electrically excited oxygen-iodine laser [4], and a supersonic wind tunnel generating vibrationally nonequilibrium flows [5]. In most of these cases, the plasma was sustained by a combination of two fully overlapping discharges, (i) high peak voltage, high repetition rate, ns pulse discharge producing electron impact ionization, and (ii) subbreakdown DC discharge, which does not generate ionization by itself but couples additional energy to the pre-ionized flow.…”

Section: Introductionmentioning

confidence: 99%

Selective generation of excited species in ns pulse/RF hybrid plasmas for plasma chemistry applications

Gulko

Jans

Richards

et al. 2020

Plasma Sources Sci. Technol.

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Hybrid plasmas, sustained by a repetitive ns pulse discharge and a sub-breakdown RF waveform in N2 and its mixtures with H2, CO, and CO2, are studied using laser diagnostics and kinetic modeling. Plasma emission images show that adding the RF waveform to the ns pulse train does not result in a discharge instability development, since the RF field does not produce additional ionization. Unlike a ns pulse/DC discharge, the ns pulse/RF plasma is sustained using a single pair of electrodes external to the discharge cell. Measurements of electronically excited molecules, N2(A3Σu +), and vibrationally excited molecules in the ground electronic state, N2(X1Σg +, v), demonstrate that these species are generated selectively. N2(A3Σu +) molecules are produced predominantly by the ns pulse discharge waveform, while vibrational excitation of the ground electronic state N2 is mainly due to the RF waveform. Strong vibrational nonequilibrium is maintained at a low translational–rotational temperature. The ns pulse/RF discharge data demonstrate that the quenching of N2(A3Σu +) is not affected by N2 vibrational excitation. Kinetic modeling shows that the rate of N2(A3Σu +) quenching in a ns pulse discharge in nitrogen is underpredicted, and the modeling predictions agree with the data only if the rate of N atom generation by electron impact dissociation of N2 is increased by approximately an order of magnitude. This suggests a significant effect of excited electronic states on the net dissociation rate. Infrared emission spectra of ns pulse/RF hybrid plasmas in CO–N2 and CO2–N2 mixtures show that the present approach also generates strong vibrational excitation of CO and CO2, with the CO yield in the CO2–N2 mixture approximately a factor of two higher compared to that in a ns pulse discharge alone. This indicates a significant contribution of the vibrationally enhanced CO2 dissociation in the hybrid plasma. The present results demonstrate that sustaining the hybrid plasma in reacting molecular gas mixtures may isolate the plasma chemical reaction pathways dominated by vibrationally excited molecules from those of electronically excited molecules and atomic species.

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Section: Introductionmentioning

confidence: 99%

Selective generation of excited species in ns pulse/RF hybrid plasmas for plasma chemistry applications

Gulko

Jans

Richards

et al. 2020

Plasma Sources Sci. Technol.

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“…Since their first development by Patel [1] and by Osgood and Eppers [2], the highest performance has been achieved in gas systems excited by various electric discharge methods and with the gas cooled to cryogenic temperatures. Efficiencies as high as 50% were reported by Grigor'yan et al [3] and powers up to 200 kW have been obtained by Dymshits et al [4] in cw systems operating on the fundamental bands. Overtone cw lasing was also achieved in similar systems by Bergman and Rich [5], with efficiencies up to 5% reported by Utkin et al [6].…”

Section: Introductionmentioning

confidence: 90%

An optically pumped carbon monoxide laser operating at elevated temperatures

Ivanov¹,

Frederickson²,

Leonov³

et al. 2013

Laser Phys.

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A flowing gas, optically pumped, CO laser has been designed and built. The laser has been made to operate on the fundamental (≈5 µm) infrared bands of the CO vibrational states. The laser is powered by absorption of continuous wave radiation from an electric-dischargeexcited CO laser. With this system, the kinetics of the establishment and maintenance of strong population inversions in CO at temperatures above 300 K is studied, independently of the complications of the electron impact processes and of other chemical channels which are present in electric discharge CO lasers. Lasing is obtained at temperatures up to 450 K, well above the cryogenic operating temperatures of conventional electric discharge CO lasers. The vibrational population distribution in the optically pumped laser is measured and the laser output power is determined as a function of the system operating parameters. Laser power conversion factors up to 14% have been observed. An optically pumped CO laser kinetic model is used to analyze the experimental results, providing insight into the details of secondary lasing kinetics.

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“…Electric discharge excited CO lasers emitting in midinfrared have demonstrated high power and efficiency, up to 200 kW [7] and 50% [8], with optimal performance achieved using electric discharges operated at cryogenic temperatures. Laser gain is obtained on rovibrational transitions of CO molecules initially populated by electron impact in the discharge, by rapid vibration-vibration (V-V) energy exchange resulting in a highly non-Boltzmann population distribution among CO vibrational levels in low-temperature environments [9,10].…”

Section: Introductionmentioning

confidence: 99%

Electrically Excited, Supersonic Flow Carbon-Monoxide Laser with Air Species in Laser Mixture

Yurkovich

Eckert

Jans

et al. 2018

Journal of Propulsion and Power

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Performance parameters of an electric discharge excited, supersonic flow CO laser operated with significant amounts of air species in the laser mixture is studied experimentally and by kinetic modeling. The results demonstrate that adding nitrogen to the CO-He mixture increases the laser power significantly, by up to a factor of 3. Adding oxygen reduces CO vibrational excitation and results in a steep laser power reduction. Adding air to the laser mixture also produces higher output power, such that the positive effect of nitrogen outweighs the negative effect of oxygen. This result indicates that a chemical CO laser, not dependent on the electric discharge for excitation, may be capable of operating in a mixture of carbon vapor and air. Performance of a supersonic flow chemical laser excited by a reaction of carbon vapor and molecular oxygen is analyzed by kinetic modeling. Peak laser power is predicted at the C vapor mole fraction of 0.2%, when 15% of energy stored in CO vibrational energy mode (4.5% of the reaction enthalpy) is converted to laser power. At higher C vapor mole fractions, flow temperature rise caused by exothermic reactions and by CO vibrational relaxation results in rapid reduction of the predicted laser power.

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<title>Continuous wave 200kW supersonic CO laser</title>

Cited by 12 publications

References 0 publications

Selective generation of excited species in ns pulse/RF hybrid plasmas for plasma chemistry applications

Selective generation of excited species in ns pulse/RF hybrid plasmas for plasma chemistry applications

An optically pumped carbon monoxide laser operating at elevated temperatures

Electrically Excited, Supersonic Flow Carbon-Monoxide Laser with Air Species in Laser Mixture

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