Spectroscopic Studies of Cold Atomic Hydrogen and Deuterium Produced in a Tokamak Edge Plasma

Hey, J. D.; Chu, C. C.; Hintz, E.

doi:10.1002/(sici)1521-3986(200004)40:1/2<9::aid-ctpp9>3.0.co;2-f

Cited by 27 publications

(80 citation statements)

References 79 publications

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“…As expected, above 12 eV present results do not model experimental results properly. to be the source of anomalously cold H atoms which have been found in a number of hydrogen plasmas (Hey et al 2000, Hey et al 1999, Hey et al 1996, Mertens & Silz 1997. In chapters 7 and 8, however, it will be shown that at higher initial vibrational states, energy differential cross sections will follow the structure of the vibrational level involved.…”

Section: Angular Differential Cross Sectionsmentioning

confidence: 97%

“…In detached divertor plasmas, vibrationally excited molecules increase plasma recombination due to dissociative attachment followed by mutual neutralization and ion conversion. Dissociative recombination, which then destroys the molecular ions present in these cold plasmas, has been found to be a dominant process (Fantz et al 1999, Behringer & Fantz 2000, Hey et al 2000.…”

Section: Overviewmentioning

confidence: 99%

“…Indeed, subtle effects in the detailed physics can have consequences for the plasma. For example, the origin of many low energy H atoms observed in tokamak plasmas (Mertens et al 2001, Tanaka et al 2000, Hey et al 1996, Hey et al 2000 is believed to be the dissociation of vibrationally excited molecules (Pospieszczyk et al 1999).…”

Section: Electron Impact Dissociation Of Hmentioning

confidence: 99%

“…Dissociation of molecular hydrogen and deuterium has been extensively studied experimentally in the plasma physics environment (Hey et al 1996, Hey et al 1999, Hey et al 2000, Mertens et al 2001) and in electron-molecular collision experiments in gases (Ogawa et al 1992). Those studies revealed the existence of cold atoms presumably produced by electron impact induced molecular dissociation.…”

Section: Electron Impact Dissociation Of Hmentioning

confidence: 99%

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Differential cross sections for near-threshold electron impact dissociation of molecular hydrogen

Trevisan

Tennyson

2001

J. Phys. B: At. Mol. Opt. Phys.

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Electron impact dissociation of molecular hydrogen is considered to be a major route to molecular break-up in cool hydrogen plasmas. Such plasmas are found in a number of astrophysical environments and in the divertor region of tokamak fusion plasma.At low energies, the major pathway for the electron impact dissociation of H is throughdissociative excited electronic state. The purpose of this work is to develop a theoretical formulation for this process for an arbitrary diatomic molecule, and to derive the formal expressions that describe the differential and total cross sections, which involve three fragments in the exit channel, and to study the electron impact dissociation of molecular hydrogen and its isotopomers at near-threshold energies.Ab initio calculations of total cross sections, angular differential cross sections, energy differential cross sections and double differential cross sections are made for the § © vibrational level of H . The effect of nuclear motion is then included in such calculations, with the dissociation taking place from the electronic ground state at different initial vibrational levels, dissociating into continuum states.Studies of mixed isotopes are performed using the R-matrix method, and total cross sections, energy differential cross sections and rate coefficients for electron impact dissociation of H , D , T , HD, HT and DT as a function of the vibrational states are presented.Finally, a scaling rule that describes integral cross sections as a function of the initial vibrational state, the reduced mass of the target molecule and the energy of the projectile electron is developed and compared against cross sections calculated accurately for the H molecule and its isotopomers.2

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Section: Angular Differential Cross Sectionsmentioning

confidence: 97%

Section: Overviewmentioning

confidence: 99%

Section: Electron Impact Dissociation Of Hmentioning

confidence: 99%

Section: Electron Impact Dissociation Of Hmentioning

confidence: 99%

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Differential cross sections for near-threshold electron impact dissociation of molecular hydrogen

Trevisan

Tennyson

2001

J. Phys. B: At. Mol. Opt. Phys.

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“…They can desorb either in the form of molecules or atoms. Measurements in TEXTOR [1][2][3][4][5][6][7][8] to molecular flux at low carbon temperature. By heating of the test limiter surface the molecular intensity dropped and the intensity of atomic species increased.…”

Section: Introductionmentioning

confidence: 99%

Catalytic probes for measuring H distribution in remote parts of hydrogen plasma reactors

Mozetič

Vesel

Drenik

et al. 2007

Journal of Nuclear Materials

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Modelling of Spectral Lines Emitted by Hydrogen Isotopes for Ionising and Recombining Plasma Conditions of Tokamak Edges

Koubiti¹,

Loch²,

Summers³

et al. 2002

Contrib. Plasma Phys.

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The plasma in the periphery or in a divertor chamber of a magnetic fusion device plays an important role in the spread of particle and heat power. Optimising the role of such a plasma requires its characterization and the understanding of all the mutual interactions of its constituents (ions, electrons, and neutrals), and also their interactions with the device materials. Among the various diagnostic methods, high‐resolution passive spectroscopy is well suitable for such a purpose since it is non‐intrusive. However, diagnostics based on this method requires an accurate modelling of the observed spectra. A fitting routine has been developed for the interpretation of Dα spectra measured in front of a neutraliser plate of the Tore‐Supra Ergodic Divertor. It takes into account both Zeeman and Doppler effects, the instrumental function, and the relaxation of the neutrals induced by elastic collisions with the plasma ions. On the other side, in order to study high‐n Balmer lines and the continuum emission of deuterium in detached divertor plasmas, a more complex lineshape code developed for Stark broadening has been recently coupled to a code accounting for line‐merging into the continuum. The code allows the convolution with a Gaussian (or a Lorentzian) to account for the Doppler broadening and the instrumental function. The Stark lineshape code has also been updated to include Zeeman effect and can be used for conditions where both Stark and Zeeman effects are important like in ITER‐divertor plasmas.

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Spectroscopic Studies of Cold Atomic Hydrogen and Deuterium Produced in a Tokamak Edge Plasma

Cited by 27 publications

References 79 publications

Differential cross sections for near-threshold electron impact dissociation of molecular hydrogen

Differential cross sections for near-threshold electron impact dissociation of molecular hydrogen

Catalytic probes for measuring H distribution in remote parts of hydrogen plasma reactors

Modelling of Spectral Lines Emitted by Hydrogen Isotopes for Ionising and Recombining Plasma Conditions of Tokamak Edges

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