Description of a flowing cascade arc plasma

Kroesen, Gmw Gerrit; Schram, DC Daan; Haas, de Jcm

doi:10.1007/bf01447263

Cited by 70 publications

(52 citation statements)

References 8 publications

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“…The ionization degree is around 8% [3,7]. With hydrogen added to the argon before it enters the arc, we assume this ionization degree to remain unchanged, at least for very low H2 seedings.…”

Section: A Thomson-rayleigh Scattering Resultsmentioning

confidence: 99%

“…The hydrogen excited level population may also arise from dielectronic recombination, but in this case an extra source term almost certainly comes in: the dissociative recombination in (7) and (10), ending in hydrogen excited states p =2,3. The H I 636.5 nm emission probably arises due to a combination of the two processes: three-particle recombination mainly at the plasma axis and dissociative recombination "wings" at the edges, where the reentrant H2 molecules are most abundant.…”

Section: A Thomson-rayleigh Scattering Resultsmentioning

confidence: 99%

“…These molecules are formed at the vessel walls and could trigger a very effective recombination channel (6) and (7).…”

Section: Discussionmentioning

confidence: 99%

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Argon-hydrogen plasma jet investigated by active and passive spectroscopic means

et al. 1994

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A supersonically expanding argon cascaded arc plasma, with difFerent amounts of hydrogen added (0, 0.7, and 1. 4 vol % H2), was studied using Thomson-Rayleigh scattering and optical emission spectroscopy. %'ith hydrogen added, the electron density profile as a function of the distance from the onset of the expansion shows a large extra ionization loss {compared to the pure argon case), especially after the stationary shock front. This anomalous loss of ionization is attributed to molecular processes, such as associative charge transfer between Ar+ and H2, and dissociative recombination of the resulting ArH+ molecular ion. Spatially resolved emission spectroscopy shows that in the expansion the radial hydrogen emission profiles are broader than the argon profiles. The addition of hydrogen appears to change the characteristic shock behavior of pure argon. For both the argon and the hydrogen system it is shown that the uppermost levels are in Saha equilibrium with their adjacent continuum.

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Section: A Thomson-rayleigh Scattering Resultsmentioning

confidence: 99%

Section: A Thomson-rayleigh Scattering Resultsmentioning

confidence: 99%

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Argon-hydrogen plasma jet investigated by active and passive spectroscopic means

et al. 1994

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“…1 The power dissipation is typically of the order of 5 kW, using an arc current of 50 A. The cascaded arc produces a thermal argon plasma at ͑sub͒atmospheric pressure, characterized by an electron temperature of 1 eV and high electron densities of 10 22 -10 23 m Ϫ3 .…”

Section: Setupmentioning

confidence: 99%

Plasma expansion in the preshock region

Burm

Goedheer

Schram

2001

Journal of Applied Physics

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The supersonic expansion of an underexpanding argon plasma from a high density arc source with small dimensions into a low-pressure vessel with large dimensions is studied by an extended one-dimensional nonlocal thermal equilibrium fluid model, called SPIRIT. In an expanding plasma the velocity increases and the pressure, the density, and the temperatures decrease severely. In this article the virtual source model is discussed first, which is a model describing the expanding plasma as originating from a virtual source. The virtual source model includes some viscosity and heat transport in simplified form, but most of the viscosity and heat transport contributions are neglected. The SPIRIT code includes the full energy and momentum balances. The inclusion of viscosity and heat sources may lead to deviations from an adiabatic and/or isentropic expansion. The SPIRIT code can analyze the deviations. When deviations are small, the isentropic expressions from gas dynamics can be used to model expanding plasma too. Model outcomes are compared with experimental data.

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“…In this Letter, we report on the study of the dynamics of a supersonic plasma jet generated by a cascaded arc [4] from a mixture of Ar and H 2 , where Ar is used as a carrier gas. We aim at an understanding of the transport of ground-state atomic hydrogen (H) from a reservoir, i.e., the plasma source, to a processed surface.…”

Section: Anomalous Atomic Hydrogen Shock Pattern In a Supersonic Plasmentioning

confidence: 99%