Charge transfer in proton–helium collisions from low to high energy

Loreau, Jérôme; Ryabchenko, Sergey; Vaeck, Nathalie

doi:10.1088/0953-4075/47/13/135204

Cited by 17 publications

(16 citation statements)

References 77 publications

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“…For more recent, but somewhat more specialized accounts we refer the reader to [149,150] These defects can be remedied by including electron translation factors (ETFs) or by using reaction coordinate techniques [151,152]. An alternative method is the hyperspherical close coupling (HSCC) approach, in which a rescaled Schrödinger equation written in terms of hyperspherical coordinates is solved (see ref.…”

Section: Uncertainty Assessment For Charge Transfer Collisionsmentioning

confidence: 99%

Uncertainty estimates for theoretical atomic and molecular data

Chung¹,

Braams²,

Bartschat³

et al. 2016

J. Phys. D: Appl. Phys.

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Sources of uncertainty are reviewed for calculated atomic and molecular data that are important for plasma modeling: atomic and molecular structure and cross sections for electron-atom, electron-molecule, and heavy particle collisions. We concentrate on model uncertainties due to approximations to the fundamental many-body quantum mechanical equations and we aim to provide guidelines to estimate uncertainties as a routine part of computations of data for structure and scattering.

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Section: Uncertainty Assessment For Charge Transfer Collisionsmentioning

confidence: 99%

Uncertainty estimates for theoretical atomic and molecular data

Chung¹,

Braams²,

Bartschat³

et al. 2016

J. Phys. D: Appl. Phys.

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“…(7), (48) REFERENCES.-(1) Burgess & Seaton (1960); (2) Schulz & Asundi (1967); (3) Dunn (1968); (4) Bates & Öpik (1968); (5) Aldrovandi & Péquignot (1973); (6) Osterbrock (1974); (7) Walkauskas & Kaufman (1975); (8) Ramaker & Peek (1976); (9) Samson & Haddad (1994); (29) Peart & Hayton (1994); (30) Stancil (1994); (31) Draine & Bertoldi (1996); (32) Olamba et al (1996); (33) (2010); (50) Loreau et al (2014). † For convenience, the reaction number for photoionization or photodissociation process is shown in boldface.…”

Section: A12 Photoionizationmentioning

confidence: 99%

Sub-parsec-scale dynamics of a dusty gas disc exposed to anisotropic AGN radiation with frequency-dependent radiative transfer

Namekata

Umemura

2016

Mon. Not. R. Astron. Soc.

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We explore the gas dynamics near the dust sublimation radius of active galactic nucleus (AGN). For the purpose, we perform axisymmetric radiation hydrodynamic simulations of a dusty gas disk of radius ≈ 1 pc around a supermassive black hole of mass 10 7 M taking into account (1) anisotropic radiation of accretion disk, (2) X-ray heating by corona, (3) radiative transfer of infrared (IR) photons reemitted by dust, (4) frequency dependency of direct and IR radiations, and (5) separate temperatures for gas and dust. As a result, we find that for Eddington ratio ≈ 0.77, a nearly neutral, dense (≈ 10 6 -8 cm −3 ), geometrically-thin (h/r < 0.06) disk forms with a high velocity (≈ 200 ∼ 3000 km s −1 ) dusty outflow launched from the disk surface. The disk temperature is determined by the balance between X-ray heating and various cooling, and the disk is almost supported by thermal pressure. Contrary to Krolik (2007), the radiation pressure by IR photons is not effective to thicken the disk, but rather compresses it. Thus, it seems difficult for a radiation-supported, geometrically-thick, obscuring torus to form near the dust sublimation radius as far as the Eddington ratio is high (∼ 1). The mass outflow rate is 0.05 -0.1 M /yr and the column density of the outflow is N H 10 21 cm −2 . To explain observed type-II AGN fraction, it is required that outflow gas is extended to larger radii (r 10 pc) or that a denser dusty wind is launched from smaller radii (r ∼ 10 4 R g ).

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“…7,8 In that model, additional atomic processes present in the edge and SOL regions plasma conditions such as proton ionization and proton-helium chargeexchange have been included. 9 The forward 1-D kinetic model revealed that electronimpact excitation and ionization are the dominating collisional mechanisms during the emission and depletion of the helium neutral gas as injected for diagnostic purposes. It also showed that interactions between the neutral helium in the gas-puff and protons were several orders of magnitude lower with respect to interactions with electrons, therefore validating the reliability of this powerful diagnostic tool.…”

Section: Introductionmentioning

confidence: 99%

“…Generalized charge-exchange rate-coefficients for the two spin systems of helium [D(nl)+He + → D + +He( 1 S, 3 S)] calculated using equation(9), and T He + = 300K 10. …”

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confidence: 99%

Evaluation of emission contributions from charge-exchange between the excited states of deuterium with He+ during diagnostic of thermal helium gas beam injection and laser-induced fluorescence

et al. 2019

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Emission contributions from charge-exchange of excited deuterium (n = 2, 3) with He + are evaluated in a 1-D kinetic collisional radiative model (CRM) in order to analyze their effects on the Thermal Helium Beam (THB) line-ratio diagnostic on ASDEX Upgrade (AUG), and Laser Induced Fluorescence (LIF) He I density measurements in ITER. Recent charge-exchange calculations show that cross-sections from excited deuterium (n = 2, 3) with He + are over 4-orders of magnitude higher than those from the ground state (n = 1), and occur at very low energies where they are more likely to interact with the thermal He + ions introduced by ionization of the diagnostic helium gas-puff injection. Higher densities of excited deuterium are typically present in the Scrape-Off Layer (SOL), Divertor, and Edge regions of Tokamaks, where the LIF and THB helium diagnostic are typically used for n HeI and simultaneous determination of electron temperatures and densities, and where contributions from charge-exchange emission may offset these values if not taken into account. The analysis presented in this work shows that due to the higher density of deuterium in the ground rather than in excited states, and the divergent behavior of deuterium and He + density profiles along the SOL and Edge regions, the deuterium-He + charge-exchange contributions to the helium puff emission are 3-orders of magnitude lower than those from electron-impact excitation. Similar plasma conditions are expected in the ITER divertor, with the exception that in the area near the strike-points and targets the electron temperature is not high enough to excite from the ground state but, deuterium, electron, and He + densities are high enough to dominate the emission from charge-exchange and recombination. These findings strengthen the assumption made in the present line-ratio model that helium emission from gas-puff into plasma is mainly dominated byelectron-excitation. It is also shown that in general, charge-exchange helium emission is 2-orders of magnitude higher than emission due to recombination. These findings suggest the importance of including charge-exchange processes as a source of neutrals in ionic fractional abundance calculations in plasmas, and helium-ash transport modeling in fusion reactors.

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Charge transfer in proton–helium collisions from low to high energy

Cited by 17 publications

References 77 publications

Uncertainty estimates for theoretical atomic and molecular data

Uncertainty estimates for theoretical atomic and molecular data

Sub-parsec-scale dynamics of a dusty gas disc exposed to anisotropic AGN radiation with frequency-dependent radiative transfer

Evaluation of emission contributions from charge-exchange between the excited states of deuterium with He+ during diagnostic of thermal helium gas beam injection and laser-induced fluorescence

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