Optical diagnostics of reactive species in atmospheric-pressure nonthermal plasma

Ono, Ryo

doi:10.1088/0022-3727/49/8/083001

Cited by 120 publications

(117 citation statements)

References 276 publications

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“…More specifically, many efforts have been devoted to identifying the key species in the jet plasma and revealing the separate or synergistic significance of those species on biological systems. Active species and relevant diagnostic methods have been well discussed in recent review papers [68][69][70].…”

Section: Plasma Jetmentioning

confidence: 99%

“…Parameters that can be obtained by OES include the electric field strength (from Stark polarization of He atomic lines [125,126] or intensity ratio of N 2 and N þ 2 [127]), identities of excited atoms and molecules, absolute concentration of active species [68] and references therein], electron density and temperature (from neutral bremsstrahlung, line broadening, line-to-continuum or line-to-line ratio, etc. ), ro-vibrational temperature of molecules (N 2 , CN, OH, NH, etc.…”

Section: Electron Diagnosticsmentioning

confidence: 99%

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Electron characterization in weakly ionized collisional plasmas: from principles to techniques

Park

Choe

Moon

et al. 2018

Advances in Physics: X

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Weakly ionized plasmas at or near 1 atm pressure, or atmospheric-pressure plasmas, have received increasing attention due to their scientific significance and potential for use in a variety of applications, particularly for medicine, agriculture, and food. However, there is a large imbalance between scientific research on plasma physics and applications, which is partly due to the considerable differences in the characteristics of these plasmas compared with those of low-pressure plasmas. This discrepancy is particularly related to the difficulty in performing plasma diagnostics for highly collisional plasmas. Information on electrons (such as the electron density and temperature) is essential since electrons play a dominant role in the generation of active species related to the physical and chemical processes inside the plasma. So far, limited diagnostics have been available for electrons such as Thomson scattering and optical emission diagnostics based on equilibrium models. Here, we review the available diagnostic methods along with their merits and limitations for characterizing electrons in weakly ionized collisional plasmas. Particular attention is paid to continuum radiation-based spectroscopy, which facilitates multidimensional imaging of electron density and temperature. The future impact of these plasmas on relevant fields (i.e. laboratory and industrial plasmas and their applications) is also addressed.

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Section: Plasma Jetmentioning

confidence: 99%

Section: Electron Diagnosticsmentioning

confidence: 99%

Electron characterization in weakly ionized collisional plasmas: from principles to techniques

Park

Choe

Moon

et al. 2018

Advances in Physics: X

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“…Microplasmas and its diagnostic are a topic of research since about four decades [10][11][12][13][14][15]. The physics of MDs or single DBDs in air and other nitrogen/oxygen gas mixtures has been studied by experimental methods, in particular electrical measurements [16][17][18][19][20][21][22][23], optical emission spectroscopy and imaging [24][25][26][27][28][29], Streak camera recording [19,30], time-correlated single photon counting [31][32][33] and laser diagnostics [34][35][36][37] as well as by simulation and modelling [38][39][40][41][42][43][44][45][46]. In [47] the correlation of the chemical reaction pathways for the oxidation of toluene and trichlorethylene with the physical behaviour of MDs was studied.…”

Section: Introductionmentioning

confidence: 99%

About the Development and Dynamics of Microdischarges in Toluene-Containing Air

Brandenburg

Jahanbakhsh

Schiorlin

et al. 2019

Plasma Chem Plasma Process

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The development of microdischarges and the inception dynamics of subsequent microdischarges in an electrode arrangement consisting of a metal pin and a hemispherical dielectric-covered electrode, operated in air with a small toluene admixture, is studied. The discharge is operated with sinusoidal high voltage. A gated ICCD camera and a current probe enable the recording of images and current pulses of the single microdischarges, respectively, while the spatio-temporally resolved development is measured with a multidimensional time-correlated single photon counting technique. The overall discharge dynamics changes significantly if a concentration of 35 ppm toluene is added to dry air. A lower high voltage amplitude than in dry air is needed for stable discharge operation. This can be explained by the lower ionization energy of toluene compared to molecular oxygen and nitrogen. The microdischarge development is the same with or without admixture, i.e. a positive (cathode directed) streamer mechanism is observed. Lower mean power is dissipated into the discharge when toluene is admixed. The main effect caused by toluene admixture is the suppression of high-energy microdischarges in case of the cathodic pin half-cycle of the sinusoidal high voltage. The influence on the inception voltage by additional ionization mechanisms and volume memory effects, the consumption of energetic electrons for toluene decomposition reactions, and the modification of the surface by plasma treatment are discussed as possible reasons.

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“…Owing to this, the experimental technique of choice must offer a high degree of spatial resolution. In this respect, a suitable method is twophoton absorption laser-induced fluorescence (TALIF), which has become a powerful tool for the detection of reactive species in plasma [9][10][11][12][13][14]. When TALIF is used for the detection of free hydrogen atoms, these atoms are usually excited by the simultaneous absorption of two laser photons with wavelength of 205.08 nm from the ground state to the state n = 3 [15,16].…”

Section: Introductionmentioning

confidence: 99%

Fluorescence (TALIF) measurement of atomic hydrogen concentration in a coplanar surface dielectric barrier discharge

Mrkvičková

Ráheľ

Dvořák

et al. 2016

Plasma Sources Sci. Technol.

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Spatially and temporally resolved measurements of atomic hydrogen concentration above the dielectric of coplanar barrier discharge are presented for atmospheric pressure in 2.2% H 2 /Ar. The measurements were carried out in the afterglow phase by means of two-photon absorption laser-induced fluorescence (TALIF). The difficulties of employing the TALIF technique in close proximity to the dielectric surface wall were successfully addressed by taking measurements on a suitable convexly curved dielectric barrier, and by proper mathematical treatment of parasitic signals from laser-surface interactions. It was found that the maximum atomic hydrogen concentration is situated closest to the dielectric wall from which it gradually decays. The maximum absolute concentration was more than 10 22 m −3 . In the afterglow phase, the concentration of atomic hydrogen above the dielectric surface stays constant for a considerable time (10 μs-1 ms), with longer times for areas situated farther from the dielectric surface. The existence of such a temporal plateau was explained by the presented 1D model: the recombination losses of atomic hydrogen farther from the dielectric surface are compensated by the diffusion of atomic hydrogen from regions close to the dielectric surface. The fact that a temporal plateau exists even closest to the dielectric surface suggests that the dielectric surface acts as a source of atomic hydrogen in the afterglow phase.

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Optical diagnostics of reactive species in atmospheric-pressure nonthermal plasma

Cited by 120 publications

References 276 publications

Electron characterization in weakly ionized collisional plasmas: from principles to techniques

Electron characterization in weakly ionized collisional plasmas: from principles to techniques

About the Development and Dynamics of Microdischarges in Toluene-Containing Air

Fluorescence (TALIF) measurement of atomic hydrogen concentration in a coplanar surface dielectric barrier discharge

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