ERO modelling of tungsten erosion and re-deposition in EAST L mode discharges

Xie, Hai; Ding, Rui; Kirschner, A.; Chen, J. L.; Ding, Fang; Mao, Haiyang; Feng, Wei; Borodin, D.; Wang, L.

doi:10.1063/1.4991457

Cited by 23 publications

(18 citation statements)

References 38 publications

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“…Before the arrival of hot plasma carried by the ELM at the divertor target, the sputtered W yield caused by D ions can be neglected be-125201-5 cause the impact energy is below the threshold energy, while the yield caused by C ions is about 0.02. With the assumption that the C concentration is a few percent in the EAST upper divertor region, [12,13] the sputtered W flux Γ w from the divertor target is about 10 −4 Γ i,0 , which is consistent with the experimental results. [12] Although the heavy metal ions such as Cu, Mo and W can cause sputtered W yield to exceed 0.1, their concentration is usually 10 −5 .…”

Section: Resultssupporting

confidence: 81%

“…For the L-mode discharges, it was found that the W erosion is governed mainly by C ion bombardment instead of molybdenum (Mo) from the first wall material. [12,13] For the H-mode with ELMs discharges, the W erosion and transport during the ELMs have been investigated. [14,15] However, effect of the multiple impurity ions on the W production with the sheath evolution during ELMs is not taken into account.…”

Section: Introductionmentioning

confidence: 99%

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Estimation of tungsten production from the upper divertor in EAST during edge localized modes*

Xiang

Men

et al. 2019

Chinese Phys. B

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During edge localized modes (ELMs), the sheath evolution in front of the Experimental Advanced Superconducting Tokamak (EAST) upper divertor is studied to estimate the sputtered tungsten (W) atoms from the divertor target. A large potential drop across the sheath is formed during ELMs by compared with inter-ELMs, and the maximum of sheath potential drop can exceed one thousand of eV in current EAST operation. Due to the enhancement of the sheath potential drop during ELMs, the W physical sputtering yield from the deuterium (D) ions and the impurity ions on the upper divertor target is found to be significant. It is established that the sputtered W yield during ELMs is at least higher by an order of magnitude than inter-ELMs, and D ions and carbon (C) ions are the main ions governing the W production for the current H-mode with ELMs discharges. With increase in the pedestal electron temperature, the maximum of the D and C ion impact energy during ELMs shows a nearly linear increase, and the D ions have sufficient impact energy to cause the strong W physical sputtering. As a consequence, the D ions may dominate the sputtered W flux from the divertor target when the C concentration is controlled less than one percent for the higher heating power H-mode with ELM discharges in near future.

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Section: Resultssupporting

confidence: 81%

Section: Introductionmentioning

confidence: 99%

Estimation of tungsten production from the upper divertor in EAST during edge localized modes*

Xiang

Men

et al. 2019

Chinese Phys. B

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“…Reproduced with permission from Ref. [22]. Copyright 2018 AIP Publishing 2.45 GHz LHW (0.4 MW) and 4 GHz LHW (2 MW) with a plasma current of 0.4 MA and toroidal magnetic field of 2.3 T. It can be seen that each puff causes a rise of the line-averaged electron density at mid-plane and the sputtered W atom flux at the divertor target also presents a drop correspondingly.…”

Section: Control Of W Sputtering Sourcementioning

confidence: 98%

“…The 3D Monte Carlo code ERO was also used to improve the understanding of W sourcing mechanisms by simulating W sputtering and re-deposition on the EAST W divertor target [22]. The photon flux of W atom emission line (400.9 nm) was simulated.…”

Section: Modeling Of W Sputtering Mechanismmentioning

confidence: 99%

Plasma–tungsten interactions in experimental advanced superconducting tokamak (EAST)

et al. 2019

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Tungsten (W) is used as the armor material of the International Thermonuclear Experimental Reactor (ITER) divertor and is regarded as the potential first wall material of future fusion reactors. One of the key challenges for the successful application of W in fusion devices is effective control of W at an extremely low concentration in plasma. Understanding and control of W erosion are not only a prerequisite for W impurity control, but also vital concerns to plasma-facing component (PFC) lifetime. Since the application of ITER-like water-cooled full W divertor in EAST in 2014, great efforts were made to investigate W erosion by experiment and simulation. A spectroscopic system was developed to provide a real-time measurement of W sputtering source. Both experiment and simulation results indicate that carbon (C) is the dominant impurity causing W sputtering in L-mode plasmas, which comes from the erosion of C plasma-facing material (PFM) in the lower divertor and the main chamber limiters. The mixture layer on the surface of W PFCs formed through redeposition or the wall coating can effectively suppress W erosion. Increasing the plasma density and radiation can reduce incident ion energy, thus alleviating W sputtering. In H-mode plasmas, control of edge localized mode (ELM) via resonant magnetic perturbation (RMP) proves to be capable of suppressing intra-ELM W erosion. The experiences and lessons from the EAST W divertor are beneficial to the design, manufacturing and operation of ITER and beyond.

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“…Therefore, a divertor must be composed of materials which have a low sputtering yield [4,6]. Since the sputtering yield of tungsten is considerably low amongst all high-temperature materials, tungsten has been considered to be a potential material for use in this application [8][9][10][11]. Although tungsten has several disadvantages, efforts have been made to overcome these disadvantages and use it as a divertor material [12][13][14][15].…”

Section: Introductionmentioning

confidence: 99%

Effect of the Surface Roughness of Tungsten on the Sputtering Yield under Helium Irradiation: A Molecular Dynamics Study

Kim

Kwon

Chang

2021

Metals

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Sputtering in a divertor is one of the key phenomena that affects plasma purity and temperature. In previous experimental studies, the term sputtering yield has been used to refer to net sputtering yield, which is defined as the difference between primary sputtering yield and re-deposition. Our simulations using molecular dynamics have confirmed that both primary sputtering yield and re-deposition are affected by particle curvature. In this study, the effect of particle curvature on the net sputtering yield was quantitatively evaluated, the results were compared to existing experimental studies, and the discrepancies with experimental results were discussed.

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ERO modelling of tungsten erosion and re-deposition in EAST L mode discharges

Cited by 23 publications

References 38 publications

Estimation of tungsten production from the upper divertor in EAST during edge localized modes*

Estimation of tungsten production from the upper divertor in EAST during edge localized modes*

Plasma–tungsten interactions in experimental advanced superconducting tokamak (EAST)

Effect of the Surface Roughness of Tungsten on the Sputtering Yield under Helium Irradiation: A Molecular Dynamics Study

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