Erosion and Carbon Deposition on Boron Exposed to Plasmas.

Ohya, Kaoru; Saji, Nobuyasu

doi:10.1585/jspf.75.416

Cited by 6 publications

(68 citation statements)

References 12 publications

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“…Further simulation calculations modeled the roughness, such as dynamic simulation of surface topography changes [19], are necessary for the detailed discussion.…”

Section: Comparison With Redeposition Patterns On C and W Roof-like Lmentioning

confidence: 99%

Simulation of hydrocarbon reflection from carbon and tungsten surfaces and its impact on codeposition patterns on plasma facing components

Ohya¹,

Kikuhara²,

Inai³

et al. 2009

Journal of Nuclear Materials

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“…Further simulation calculations modeled the roughness, such as dynamic simulation of surface topography changes [19], are necessary for the detailed discussion.…”

Section: Comparison With Redeposition Patterns On C and W Roof-like Lmentioning

confidence: 99%

Simulation of hydrocarbon reflection from carbon and tungsten surfaces and its impact on codeposition patterns on plasma facing components

Ohya¹,

Kikuhara²,

Inai³

et al. 2009

Journal of Nuclear Materials

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“…Thus, chemically eroded ethane and propane families should be considered in the estimation of tritium retention. In previous studies, redeposition profiles and characteristics of CH 4 [2] and of C 2 H 4 and C 2 H 6 [3] were investigated using a simple model for divertor plasma region (constant plasma temperature and density). Further, in Ref.…”

Section: Introductionmentioning

confidence: 99%

“…Further, in Ref. 3, poloidal distributions of redeposited carbons/hydrocarbons on the divertor surface were calculated. However, characteristics of author's e-mail: kawazome@di.kagawa-nct.ac.jp * ) This article is based on the presentation at the 20th International Toki Conference (ITC20).…”

Section: Introductionmentioning

confidence: 99%

Redeposition Characteristics of Heavy Hydrocarbon Molecules on a Divertor Plate

Kawazome

Ohya

Kawata

2011

Plasma and Fusion Research

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In this study, local redeposition characteristics of hydrocarbon molecules from the ethane family are investigated using Monte Carlo simulation. Information about redeposition characteristics is required to estimate tritium retention via redeposition with chemically eroded hydrocarbon molecules. For the condition of multiple reflections at divertor surface and a plasma density of 1.0 × 10 19 m −3 , the local redeposition characteristics for injection of ethane family (C 2 H 2 , C 2 H 4 , C 2 H 6 ) have been investigated for plasma temperatures ranging from 1 to 100 eV. The number of redeposited hydrocarbon molecules increases with plasma temperature because of the increase in impinging particle energy. The increase in sheath potential results in the increase in particle energy. For plasma temperatures lower than 5 eV, there is a sudden increase in the number of redeposited particles with plasma temperature because of the increase in the number of impinging molecular ions. Sheath field acceleration is the main mechanism that causes the ions to move to the divertor plate, and the exponential increase in the number of redeposited particles results from the increase in hydrocarbon break-up products in the sheath potential region.

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“…For example, when the temperature is 1 eV, the rate coefficient of electron impact dissociation D CH 4 and of electron impact ionization S CH 4 are three and five orders of magnitude less than that of charge exchange ionization CX CH 4 , respectively (CX CH 4 ∼ 10 −9 m 3 /s, D CH 4 ∼ 72, respectively, and emission event do not vary linearly with the excitation rate coefficient. These results are caused by increase of additional emission events from reflected molecules at the divertor plate [11]. The friction force, which toward the divertor plate, at the plasma density of 10 18 m −3 is smaller than these at the plasma density of 10 19 and 10 20 m −3 .…”

Section: Resultsmentioning

confidence: 89%

“…The rate coefficients for reactions (a) -(d) are referred from data set of Janev and Reiter [9,10]. Reflection coefficients of all of the dissociation products on the surface are evaluated by a classical molecular dynamics simulation [11]. Hydrocarbon molecule ions, which are produced by the reaction with ionization process, gy-rate due to the Lorentz force and move along the direction parallel to the magnetic field lines due to a force F .…”

Section: Simulation Modelmentioning

confidence: 99%

Calculation of D/XB Values of Hydrocarbon Molecules in Tokamak Edge Plasmas

Kawazome

Ohya

Inai

et al. 2010

Plasma and Fusion Research

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In order to investigate the dependence of effective inverse photon-efficiency D/XB values on the plasma parameters, we have been performed calculations of effective D/XB values by Monte Carlo method. Photon fluxes are converted into particle fluxes with aid of D/XB values. A D/XB value is critical factor in the study of chemical erosion by spectroscopic measurement. In modeled tokamak edge plasma, transfer of hydrocarbon molecules (CH 4 , C 2 H x (x = 2,4,6), C 3 H y (y = 4,6,8)) and CH and C 2 emissions have been simulated. The plasma temperature ranged from 1 eV to 100 eV and the plasma densities are 10 18 m −3 , 10 19 m −3 and 10 20 m −3. In the temperature region of less than 3 eV, the calculated D/XB values increase with decreasing temperature due to decreasing of emission counts. In the high temperature region (≥ 10 eV), the D/XB values increase with a rise in the temperature due to decrease of number of fragment of type CH and C 2 .

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Erosion and Carbon Deposition on Boron Exposed to Plasmas.

Cited by 6 publications

References 12 publications

Simulation of hydrocarbon reflection from carbon and tungsten surfaces and its impact on codeposition patterns on plasma facing components

Simulation of hydrocarbon reflection from carbon and tungsten surfaces and its impact on codeposition patterns on plasma facing components

Redeposition Characteristics of Heavy Hydrocarbon Molecules on a Divertor Plate

Calculation of D/XB Values of Hydrocarbon Molecules in Tokamak Edge Plasmas

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