Aerodynamic Separation Effect on Gas and Isotope Mixtures Induced by Invasion of the Free Jet Shock Wave Structure

Campargue, R.

doi:10.1063/1.1673220

Cited by 90 publications

(31 citation statements)

References 18 publications

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“…In the plasmas that are discussed in this paper, the ionization degree is 10% or even much less. The plasma expansion is then almost like that of a hot gas: [16][17][18][19][20] while expanding from the source, it accelerates and both the temperature and the density decrease. When the jet total pressure 21 approaches the background pressure, the flow goes through a stationary shock, after which the plasma expands subsonically.…”

Section: Rarefied Plasma Expansionmentioning

confidence: 99%

Inflow and shock formation in supersonic, rarefied plasma expansions

Vankan

Mazouffre²,

Engeln

et al. 2005

Physics of Plasmas

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In this paper the physics of plasma expansion in the rarefied regime is reviewed. Densities, temperatures, and velocity distributions in argon, hydrogen, and nitrogen expansions that have been measured using laser scattering and fluorescence techniques are compared. The velocity distributions in the region of the expansion where the density is below the background density show a bimodal character. It is interpreted in terms of a component expanding from the source and a component flowing into the plasma expansion from the periphery. Also in the shock of the expansion, bimodal velocity distributions are encountered. These distributions show the gradual change in the flow from supersonic to subsonic-the formation of the shock. From a comparison of the three expansions, a general view of the shock formation is derived. This new insight leads to a better understanding of how the chemical reactivity of the usually impenetrable, supersonic plasma can be used most efficiently.

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Section: Rarefied Plasma Expansionmentioning

confidence: 99%

Inflow and shock formation in supersonic, rarefied plasma expansions

Vankan

Mazouffre²,

Engeln

et al. 2005

Physics of Plasmas

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“…7͒ data it is concluded that the forward flux of H is not conserved over the shock region in the expansion of a thermal Ar-H plasma, which is a clear deviation of ''normal'' supersonic expansion behavior as described by supersonic expansion theory. [43][44][45] The in-depth physical discussion of the expansion properties of the plasma jet is left to a separate paper. 32,35 …”

Section: Velocity Measurementsmentioning

confidence: 99%

Quantitative two-photon laser-induced fluorescence measurements of atomic hydrogen densities, temperatures, and velocities in an expanding thermal plasma

Boogaarts

Mazouffre

Brinkman

et al. 2002

Review of Scientific Instruments

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We report on quantitative, spatially resolved density, temperature, and velocity measurements on ground-state atomic hydrogen in an expanding thermal Ar-H plasma using two-photon excitation laser-induced fluorescence ͑LIF͒. The method's diagnostic value for application in this plasma is assessed by identifying and evaluating the possibly disturbing factors on the interpretation of the LIF signal in terms of density, temperature, and velocity. In order to obtain quantitative density numbers, the LIF setup is calibrated for H measurements using two different methods. A commonly applied calibration method, in which the LIF signal from a, by titration, known amount of H generated by a flow-tube reactor is used as a reference, is compared to a rather new calibration method, in which the H density in the plasma jet is derived from a measurement of the two-photon LIF signal generated from krypton at a well-known pressure, using a known Kr to H detection sensitivity ratio. The two methods yield nearly the same result, which validates the new H density calibration. Gauging the new ''rare gas method'' by the ''flow-tube reactor method,'' we find a krypton to hydrogen two-photon excitation cross section ratio Kr ͑2͒ / H (2) of 0.56, close to the reported value of 0.62. Since the H density calibration via two-photon LIF of krypton is experimentally far more easy than the one using a flow-tube reactor, it is foreseen that the ''rare gas method'' will become the method of choice in two-photon LIF experiments. The current two-photon LIF detection limit for H in the Ar-H plasma jet is 10 15 m Ϫ3 . The accuracy of the density measurements depends on the accuracy of the calibration, which is currently limited to 33%. The reproducibility depends on the signal-to-noise ͑S/N͒ ratio in the LIF measurements and is orders of magnitude better. The accuracy in the temperature determination also depends on the S/N ratio of the LIF signal and on the ratio between the Doppler-width of the transition and the linewidth of the excitation laser. Due to the small H mass, the current linewidth of the UV laser radiation is never the accuracy limiting factor in the H temperature determination, even not at room temperature. Quantitative velocity numbers are obtained by measuring the Doppler shift in the H two-photon excitation spectrum. Both the radial and axial velocity components are obtained by applying a perpendicular and an antiparallel excitation configuration, respectively. The required laser frequency calibration is accomplished by simultaneously recording the I 2 absorption spectrum with the fundamental frequency component of the laser system. This method, which is well-established in spectroscopic applications, enables us to achieve a relative accuracy in the transition frequency measurement below 10 Ϫ6 , corresponding to an accuracy in the velocity of approximately 200 m/s. This accuracy is nearly laser linewidth limited.

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“…The diffusion of background gases into the isentropic expansion can result in signi®cant modi®cation of the mixed gas beam composition ratio, primarily favouring the lighter component. 34 As well, the placement or location of the skimmer can signi®cantly affect the composition of the beam which is ef®ciently transmitted into the second stage. 30 To avoid large deviations, the skimming should be performed well within the Mach disk.…”

Section: Resultsmentioning

confidence: 99%

Use of Ar–He mixed gas plasmas for furnace atomisation plasma ionisation mass spectrometry (FAPIMS)

Stewart

Sturgeon

2000

J. Anal. At. Spectrom.

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Access and use of this website and the material on it are subject to the Terms and Conditions set forth at Use of Ar-He mixed gas plasmas for furnace atomization plasma ionization mass spectrometry (FAPIMS) Stewart, I. I.; Sturgeon, R. NRC Publications Record / Notice d'Archives des publications de CNRC:http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/ctrl?action=rtdoc&an=8897283&lang=en http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/ctrl?action=rtdoc&an=8897283&lang=fr READ THESE TERMS AND CONDITIONS CAREFULLY BEFORE USING THIS WEBSITE.http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/jsp/nparc_cp.jsp?lang=en Vous avez des questions? Nous pouvons vous aider. Pour communiquer directement avec un auteur, consultez la première page de la revue dans laquelle son article a été publié afin de trouver ses coordonnées. Si vous n'arrivez pas à les repérer, communiquez avec nous à PublicationsArchive-ArchivesPublications@nrc-cnrc.gc.ca.

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Aerodynamic Separation Effect on Gas and Isotope Mixtures Induced by Invasion of the Free Jet Shock Wave Structure

Cited by 90 publications

References 18 publications

Inflow and shock formation in supersonic, rarefied plasma expansions

Inflow and shock formation in supersonic, rarefied plasma expansions

Quantitative two-photon laser-induced fluorescence measurements of atomic hydrogen densities, temperatures, and velocities in an expanding thermal plasma

Use of Ar–He mixed gas plasmas for furnace atomisation plasma ionisation mass spectrometry (FAPIMS)

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