Comparison of the electron density measurements using Thomson scattering and emission spectroscopy for laser induced breakdown in one atmosphere of helium

Nedanovska, E.; Nersisyan, G.; Morgan, Thomas J.; Hüwel, Lutz; Lewis, Ciaran; Riley, David; Graham, W. G.

doi:10.1063/1.3672817

Cited by 21 publications

(17 citation statements)

References 15 publications

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“…The shortest probe delay can only be around 500 ns after the optical breakdown, due to the perturbation of the plasma by the probe laser [42][43][44]. These characteristics contrast to the diagnostic methods, such as Stark broadening [13,29,45,46] and interferometric methods [47,48], requiring indirect relations to convert into the plasma parameters with accessibility to the earlier moments.…”

Section: Diagnostics Overviewmentioning

confidence: 99%

A study of velocity, temperature, and density in the plasma generated by laser-induced breakdowns

Nishihara

Freund

Elliott

2019

J. Phys. D: Appl. Phys.

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The paper presents velocity measurements of shock-induced flow field, leading to vortex generation and plasma deformation in air. Femtosecond-laser electronic excitation tagging (FLEET) velocimetry was performed at the times Δt = 3, 20, 50, and 100 µs post laser-induced breakdown. Emissions over Δt = 3–10 µs showed the propagations of the initially elliptic shock, transitioning into a spherical front. The shock emanated along the laser axis causes the flow outward, and then the pressure gradient generated by the rarefaction wave drives the inward flow at later moments, with the velocity magnitude approaching a steady-state value of 40 m s−1. Temporal velocity evolution was compared with non-self-similar solutions behind the propagating shock, which are sensitive to the size of the energy deposition, and the use of the measured initial plasma diameter reproduced the experiment. There establishes a region of uniform velocity around 35 m s−1 in the air-flow running through the plasma, which triggers the roll-up of the plasma surface by a large-scale vortex, providing the detail of flow field evolution from the shock propagation to the plasma deformation. A collective Thomson scattering and hybrid fs/ps pure rotational coherent anti-Stokes Raman scattering (CARS) were also performed to gain insight into the high-temperature plasma. An effective electron–ion recombination rate of 2 10−12 cm3 s−1 was measured at Δt = 0.5–10 µs, during a dynamic plasma expansion and compression. When the shock resides close to the plasma at Δt = 0.5–1 µs, the temperature distributions were found to follow the similarity law.

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Section: Diagnostics Overviewmentioning

confidence: 99%

A study of velocity, temperature, and density in the plasma generated by laser-induced breakdowns

Nishihara

Freund

Elliott

2019

J. Phys. D: Appl. Phys.

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“…[1][2][3][4][5][6][7][8][9][10][11] Manifold devices are used to generate stable microdischarges, inluding DC, RF, Microwave, Laser etc. [12][13][14][15] based on the different applied operation modes. Among all kinds of non-equilibrium plasma systems, the microplasma in close proximity to the water surface is promising in fabrication and engineering of nanoparticles and quantum dots as shown in the previous research.…”

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confidence: 99%

Heat transport of nitrogen in helium atmospheric pressure microplasma

Zhong

2013

Applied Physics Letters

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Stable DC atmospheric pressure normal glow discharges in ambient air were produced between the water surface and the metallic capillary coupled with influx of helium gas. Multiple independent repeated trials indicated that vibrational temperature of nitrogen rises from 3200 to 4622 K, and rotational temperature of nitrogen decreases from 1270 to 570 K as gas flux increasing from 20 to 80 sccm and discharge current decreasing from 11 to 3 mA. Furthermore, it was found that the vibrational degree of the nitrogen molecule has priority to gain energy than the rotational degree of nitrogen molecule in nonequilibrium helium microplasma.Comment: 4 pages, 5 figures, accepted by AP

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“…And, laser-induced optical effects such as photodetachment, photon-ionization, or electron heating may occur if high laser power is used in measurements, and need to be checked by measuring the signal as a function of laser power. More details about the Thomson scattering approach can be found in [13,39,41,[43][44][45][46][47][48].…”

Section: Electron Density and Temperaturementioning

confidence: 99%

Advanced Optical Diagnostics of Atmospheric Pressure Plasma

Xiong¹

2019

Atmospheric Pressure Plasma - From Diagnostics to Applications

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Atmospheric-pressure plasma has been employed in various applications including bio-medicine, environmental pollution control, material processing. Diagnostic characterization of plasma sources is critical and indispensable for plasma control and achieving optimized treatment efficiency. In this chapter we will introduce several advanced optical techniques to visualize the detailed physicaland-chemical properties of atmospheric-pressure discharges. Non-invasive approaches of optical emission spectroscopy (OES), schlieren or shadowgraph, invasive methods of active laser spectroscopy including laser-induced fluorescence (LIF), laser or broadband absorption, cavity ring-down spectroscopy (CRDS), and laser scattering are illustrated. Basic plasma parameters of gas temperature, electron density and temperature, electric field strength, and reactive chemical gaseous species (O, H, N, OH, NO, O 3 , etc.) are able to be monitored. Comparisons and comments of these approaches are provided depending on diagnostic purposes.

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Comparison of the electron density measurements using Thomson scattering and emission spectroscopy for laser induced breakdown in one atmosphere of helium

Cited by 21 publications

References 15 publications

A study of velocity, temperature, and density in the plasma generated by laser-induced breakdowns

A study of velocity, temperature, and density in the plasma generated by laser-induced breakdowns

Heat transport of nitrogen in helium atmospheric pressure microplasma

Advanced Optical Diagnostics of Atmospheric Pressure Plasma

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