Hyperthermal hydrogen atoms in argon-hydrogen atmospheric pressure microplasma jet

Oliveira, Carlos Yure B.; Corrêa, J. A. Souza; Gomes, Marcelo Pego; Sismanoglu, Bogos Nubar; Amorim, J.

doi:10.1063/1.2967016

Cited by 42 publications

(33 citation statements)

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“…The significantly broadened Balmer or Lyman series emitted by hydrogen or deuterium atoms is a highly debated phenomenon observed in the atmosphere of stellar and planetary plasmas [1,2], low temperature plasmas of hollow cathodes [3], radio frequency induction plasmas [4] or microplasma jets at atmospheric pressures [5]. In many cases the presence of noble gases stimulates the emission of hydrogen lines, i.e., either the intensity is increased or the lines become extensively broadened.…”

Section: Introductionmentioning

confidence: 99%

Emission of fast non-Maxwellian hydrogen atoms in low-density laboratory plasma

Brandt

Marchuk

Pospieszczyk

et al. 2017

AIP Conference Proceedings

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Abstract. The source of strong and broad emission of the Balmer-α line in mixed plasmas of hydrogen (or deuterium) and noble gases in front of metallic surfaces is a subject of controversial discussion of many plasma types. In this work the excitation source of the Balmer lines is investigated by means of optical emission spectroscopy in the plasma device PSI-2. Neutral fast non-Maxwellian hydrogen atoms are produced by acceleration of hydrogen ions towards an electrode immersed into the plasma. By variation of the electrode potential the energy of ions and in turn of reflected fast atoms can be varied in the range of 40 − 300 eV. The fast atoms in front of the electrode are observed simultaneously by an Echelle spectrometer (0.001 nm/channel) and by an imaging spectrometer (0.01 nm/channel) up to few cm in the plasma. Intense excitation channels of the Balmer lines are observed when hydrogen is mixed with argon or with krypton. Especially in Ar-H and Ar-D mixed plasmas the emission of fast hydrogen atoms is very strong. Intermixing hydrogen with other noble gases (He, Ne or Xe) one observes the same effect however the emission is one order of magnitude less compared to Kr-H or Kr-D plasmas. It is shown, that the key process, impacting this emission, is the binary collision between the fast neutral hydrogen atom and the noble gas atom. Two possible sources of excitation are discussed in details: one is the excitation of hydrogen atoms by argon atoms in the ground state and the second one is the process of the so-called excitation transfer between the metastable states of noble gases and hydrogen. In the latter case the atomic data for excitation of Balmer lines are still not available in literature. Further experimental investigations are required to conclude on the source process of fast atom emission.

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Section: Introductionmentioning

confidence: 99%

Emission of fast non-Maxwellian hydrogen atoms in low-density laboratory plasma

Brandt

Marchuk

Pospieszczyk

et al. 2017

AIP Conference Proceedings

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“…8,9,11 A possible explanation for such selective heating of H atoms may be connected with the main creation processes of excited H atoms, namely, ion conversion and electron impact dissociation. Furthermore, hyperthermal hydrogen atoms have surprisingly been detected at atmospheric pressure Ar-H 2 microplasma jets, where the H͑n =3͒ temperatures were found to range from 12,000 to 19,600 K. 12 It is now clear that hydrogen line broadening causes controversy so that more experimental observations are currently needed in order to try to elucidate the mechanisms and processes behind this phenomenon in different types of discharges. The aim of this experimental work is to address some of these problems.…”

Section: Introductionmentioning

confidence: 99%

Spectroscopic investigation of wave driven microwave plasmas

Wijtvliet

Felizardo²,

Tatarova³

et al. 2009

Journal of Applied Physics

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Document VersionPublisher's PDF, also known as Version of Record (includes final page, issue and volume numbers)Please check the document version of this publication:• A submitted manuscript is the author's version of the article upon submission and before peer-review. There can be important differences between the submitted version and the official published version of record. People interested in the research are advised to contact the author for the final version of the publication, or visit the DOI to the publisher's website.• The final author version and the galley proof are versions of the publication after peer review.• The final published version features the final layout of the paper including the volume, issue and page numbers. Link to publication General rightsCopyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.• Users may download and print one copy of any publication from the public portal for the purpose of private study or research.• You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal ? Take down policyIf you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. Large H atom line broadening was found throughout the volume of surface wave generated He-H 2 and H 2 microwave plasmas at low pressures. The measured Doppler temperatures corresponding to the H ␤ , H ␥ , H ␦ , H , and H line profiles were found to be higher than the rotational temperature of the hydrogen molecular Fulcher-␣ band and the Doppler temperature of the 667.1 nm singlet He line. No excessive broadening has been found. The Lorentzian and Gaussian widths as determined by fitting the spectral lines with a Voigt profile increase with the principal quantum number of the upper level. In contrast, no such dependence for the Gaussian width has been observed in an Ar-H 2 discharge. No population inversion has been observed from measurements of the relative intensities of transitions within the Balmer series.

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“…The analysis of Balmer line shapes has usually been applied to detect energetic hydrogen atoms in various types of gas discharges [1,2]. The presence of such atoms results in extended "wings" in the line profiles.…”

Section: Introductionmentioning

confidence: 99%