Determination of gas-temperature and velocity profiles in an argon thermal-plasma jet by laser-light scattering

Snyder, S. C.; Reynolds, L. D.; Lassahn, G.D.; Fincke, J. R.; Shaw, C. B.; Kearney, R. J.

doi:10.1103/physreve.47.1996

Cited by 51 publications

(17 citation statements)

References 18 publications

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“…Generally they can be divided as based on emission spectroscopy [12], laser absorption spectroscopy [12][13][14][15] and laser scattering [16]. In case of emission spectroscopy the T a can for instance be obtained from the rotational temperature of excited molecular species.…”

Section: Introductionmentioning

confidence: 99%

Rayleigh scattering on a microwave surfatron plasma to obtain axial profiles of the atom density and temperature

Hübner

Iordanova

Palomares

et al. 2012

Eur. Phys. J. Appl. Phys.

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Please check the document version of this publication:• A submitted manuscript is the version of the article upon submission and before peer-review. There can be important differences between the submitted version and the official published version of record. People interested in the research are advised to contact the author for the final version of the publication, or visit the DOI to the publisher's website.• The final author version and the galley proof are versions of the publication after peer review.• The final published version features the final layout of the paper including the volume, issue and page numbers. Link to publication General rightsCopyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.• Users may download and print one copy of any publication from the public portal for the purpose of private study or research.• You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal. Abstract. The axial dependency of the central-axis value of the heavy particle density and temperature of surface-wave plasmas is studied using Rayleigh scattering (RyS). The plasma is generated at a frequency of 2.45 GHz in argon by a surfatron operating under the standard settings of a power of 45 W, a flow rate of 50 sccm and a pressure of 20 mbar. To investigate the effect of the pressure on the gas temperature, we also investigated 6 and 10 mbar plasmas. By using a two-dimensional intensified CCD array we could determine and eliminate the influence of false stray light, a major disturbing factor in the determination of the Rayleigh signal. In order to trace the energy fluxes that determine the gas temperature, we performed Thomson scattering so that the properties of the electron gas are known. It is found that the gas temperature, T a, depends on the wall temperature and the product of the gas pressure and the electron pressure. The latter implies that Ta follows the electron density axially, meaning that it is highest at the launcher and decreases monotonically in the wave propagation direction. The maximum gas temperature of around Ta = 800 K is found close to the launcher for the highest gas pressure of 20 mbar. For lower pressures we find lower Ta values. The extrapolation of Ta toward the end of the plasma column leads to a temperature of about 320 K. This study reveals that, for the argon plasmas under study, the central-axis values of the gas temperature are determined by the balance between the heating of the gas by means of elastic electron collisions and the cooling due to heat conduction from the center to the wall.

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Section: Introductionmentioning

confidence: 99%

Rayleigh scattering on a microwave surfatron plasma to obtain axial profiles of the atom density and temperature

Hübner

Iordanova

Palomares

et al. 2012

Eur. Phys. J. Appl. Phys.

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“…In Figure 10, the temperature data are shown with the different Rayleigh cross sections included. It was found that without any optimization to the plasma, the gas in the plasma center can reach temperatures of up to 5,000 K. It has been shown in Ar plasmas that the Thomson scattering and scattering from excited species becomes significant if the temperature reaches the order of 10,000 K 18,19,20 , making the temperature measurement unreliable. Given the values of the differential cross sections for Rayleigh and Thomson scattering of 0.148·10 -30 m 2 and 7.94·10 -30 m 2 , respectively, an ionization degree of 1.9·10 -4 would be necessary for a…”

Section: Representative Resultsmentioning

confidence: 99%

Non-equilibrium Microwave Plasma for Efficient High Temperature Chemistry

Bekerom

Harder

Minea

et al. 2017

JoVE

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A flowing microwave plasma based methodology for converting electric energy into internal and/or translational modes of stable molecules with the purpose of efficiently driving non-equilibrium chemistry is discussed. The advantage of a flowing plasma reactor is that continuous chemical processes can be driven with the flexibility of startup times in the seconds timescale. The plasma approach is generically suitable for conversion/ activation of stable molecules such as CO 2 , N 2 and CH 4 . Here the reduction of CO 2 to CO is used as a model system: the complementary diagnostics illustrate how a baseline thermodynamic equilibrium conversion can be exceeded by the intrinsic non-equilibrium from high vibrational excitation. Laser (Rayleigh) scattering is used to measure the reactor temperature and Fourier Transform Infrared Spectroscopy (FTIR) to characterize in situ internal (vibrational) excitation as well as the effluent composition to monitor conversion and selectivity.

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“…The theory of Thomson scattering is explicated by many literatures [7][8][9][10][11]13]. Figure 2 shows the comparison between electron temperature for the pure helium arc with the water-cooled copper anode (left side) and that for the helium arc during welding (right side) under the same condition of 150 A in arc current and 5 mm in arc length.…”

Section: Temperature Distributions 21 Experimental Set Upmentioning

confidence: 99%

“…Recently, some of non-LTE states in GTA plasma were showed in case of the pure argon. Snyder et al directly measured temperatures of electron and heavy particle in DC plasma jet [7] and free-burning arc [8] at atmospheric pressure by the method of laser scattering measurement which needs no assumption of LTE. They showed that electron temperature was different from heavy particle temperature.…”

Section: Introductionmentioning

confidence: 99%

Number Density Distributions of Metal Vapor in Helium Gas Tungsten Arcs

Tsujimura

Terasaki

Yamamoto

et al. 2010

Trans. Mat. Res. Soc. Japan

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In order to investigate effects of metal vapor on the plasma state in welding process, electron temperature in helium Gas Tungsten Arc (GTA) plasma during welding was measured by using the laser scattering method. Furthermore, number density distributions of metal neutrals and ions were also measured by using the spectroscopic analysis. Our results showed that plasma during welding consisted of two plasma regions, namely, pure helium plasma region and quasi-metal plasma region.

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Determination of gas-temperature and velocity profiles in an argon thermal-plasma jet by laser-light scattering

Cited by 51 publications

References 18 publications

Rayleigh scattering on a microwave surfatron plasma to obtain axial profiles of the atom density and temperature

Rayleigh scattering on a microwave surfatron plasma to obtain axial profiles of the atom density and temperature

Non-equilibrium Microwave Plasma for Efficient High Temperature Chemistry

Number Density Distributions of Metal Vapor in Helium Gas Tungsten Arcs

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