Measurement of OH density and air–helium mixture ratio in an atmospheric-pressure helium plasma jet

Yonemori, Seiya; Nakagawa, Yusuke; Ono, Ryo; Oda, Tetsuji

doi:10.1088/0022-3727/45/22/225202

Cited by 139 publications

(105 citation statements)

References 40 publications

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“…Additionally, the electron drift velocity υ e strongly depends on the gas phase composition, see figure 1. The gas composition varies significantly along the axis of the APPJ due to air diffusion and the air mole fraction can reach 10% on a distance of 10 mm from the nozzle [25] which can result in serious errors in the estimations of n e by the use of equation (1).…”

Section: Current and Voltagementioning

confidence: 99%

Electron density measurement in atmospheric pressure plasma jets: Stark broadening of hydrogenated and non-hydrogenated lines

Nikiforov

Leys

González

et al. 2015

Plasma Sources Sci. Technol.

197

179

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Electron density is one of the key parameters in the physics of a gas discharge. In this contribution the application of the Stark broadening method to determine the electron density in low temperature atmospheric pressure plasma jets is discussed. An overview of the available theoretical Stark broadening calculations of hydrogenated and non-hydrogenated atomic lines is presented. The difficulty in the evaluation of the fine structure splitting of lines, which is important at low electron density, is analysed and recommendations on the applicability of the method for low ionization degree plasmas are given. Different emission line broadening mechanisms under atmospheric pressure conditions are discussed and an experimental line profile fitting procedure for the determination of the Stark broadening contribution is suggested. Available experimental data is carefully analysed for the Stark broadening of lines in plasma jets excited over a wide range of frequencies from dc to MW and pulsed mode. Finally, recommendations are given concerning the application of the Stark broadening technique for the estimation of the electron density under typical conditions of plasma jets.

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Section: Current and Voltagementioning

confidence: 99%

Electron density measurement in atmospheric pressure plasma jets: Stark broadening of hydrogenated and non-hydrogenated lines

Nikiforov

Leys

González

et al. 2015

Plasma Sources Sci. Technol.

197

179

View full text Add to dashboard Cite

show abstract

“…If rate coefficients are well known, however, it is possible to infer the gas composition using the collisional data measured by LIF. In [21] for a plasma jet expanding into free air the total electronic quenching was measured from the LIF pulse decay, and the concentration of humid air penetrating into the jet was calculated for a fixed air plus water vapour mixture. A plasma jet expanding into ambient humid air and hitting a liquid surface, instead, has not a fixed humid air composition.…”

Section: Gas Mixture Compositionmentioning

confidence: 99%

Laser induced fluorescence in atmospheric pressure discharges

Dilecce

Martini

Tosi

et al. 2015

Plasma Sources Sci. Technol.

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Abstract.This paper offers an outline of Laser Induced Fluorescence (LIF) diagnostics and practical recommendations for its use in atmospheric pressure discharges. LIF principles, technical requirements and rationalization of experimental outcomes by modelling are addressed. Important issues that are particularly relevant to small scale, spatially inhomogeneous discharges, like plasma-jets, are emphasized. For the first time, all collision processes and the spatial non-homogeneity of the laser beam are together accounted for in the LIF model. Saturation characteristics are discussed and used for the assessment of model parameters. A calibration procedure is discussed and implemented. Gas temperature measurements by LIF are also addressed. The whole description of the technique is given, without loss of generality, through the example of its application to the OH radical. Notes on other diatomic radicals, CH, NO and CN, are given along the paper. Some results in a RF plasma-jet are presented as an example of application in a discharge system where all the concepts developed in the paper are applied.

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“…5 It assumes that the molecules excited to the upper state remain in the original excited level until spontaneous emission. 5,10 Unfortunately, it is not valid for plasma jet at high pressure due to non-Boltzmann distribution in the upper energy levels deduced from the time-resolved LIF spectrum of OH A 2 P þ state. In the present work, we consider that the ground-state OH radicals X 2 P, v 00 ¼ 0 is excited to the A 2 P þ , v 0 ¼ 1 by the laser with the fluorescence appearing from v 00 -v 0 ¼ 0-0 and v 00 -v 0 ¼ 1-1 bands.…”

Section: -6mentioning

confidence: 99%

“…In addition, a model taking into account both RET and VET processes is implemented in order to calculate the absolute density and 2D map distribution of OH radicals. It has to be noted that, the absolute density of OH radicals in plasma jets has already been detected by LIF 10 and cavity ring-down spectroscopy. 11 However, not enough attention has been paid to the influence of water content on spatial distribution of OH radicals in the studied plasmas, as well as on the fluorescence generation processes after laser excitation of OH radicals.…”

Section: Introductionmentioning

confidence: 99%

OH radicals distribution in an Ar-H2O atmospheric plasma jet

Nikiforov

Xiong

et al. 2013

Physics of Plasmas

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Recently, plasma jet systems found numerous applications in the field of biomedicine and treatment of temperature-sensitive materials. OH radicals are one of the main active species produced by these plasmas. Present study deals with the investigation of RF atmospheric pressure plasma jet in terms of OH radicals production by admixture of H 2 O into argon used as a feed gas. Generation of OH radicals is studied by laser-induced fluorescence spectroscopy. The excitation dynamics of OH radicals induced by the laser photons is studied by time-resolved spectroscopy. It is shown that vibrational and rotational energy transfer processes, which are sensitive to the surrounding species, can lead to the complication in the OH radicals diagnostics at high pressure and have to be considered during experiments. The axial and radial 2D maps of absolute densities of hydroxyl radicals at different water contents are obtained. The highest density of 1.15 Â 10 20 m À3 is measured in the plasma core for the case of 0.3% H 2 O. In the x-y-plane, the OH density steeply decreases within a range of 62 mm from its maximum value down to 10 18 m À3 . The effect of H 2 O addition on the generation of OH radicals is investigated and discussed. V C 2013 AIP Publishing LLC. [http://dx

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Measurement of OH density and air–helium mixture ratio in an atmospheric-pressure helium plasma jet

Cited by 139 publications

References 40 publications

Electron density measurement in atmospheric pressure plasma jets: Stark broadening of hydrogenated and non-hydrogenated lines

Electron density measurement in atmospheric pressure plasma jets: Stark broadening of hydrogenated and non-hydrogenated lines

Laser induced fluorescence in atmospheric pressure discharges

OH radicals distribution in an Ar-H2O atmospheric plasma jet

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