Influence of impurity seeding on the plasma radiation in the EAST tokamak

Dong, Liping; Duan, Yanmin; Chen, Kaiyun; Yang, Xiuda; Zhang, Ling; Xu, Feng; Mao, Shifeng; Wu, Zhenwei; Hu, Liqun

doi:10.1088/2058-6272/aab20c

Cited by 10 publications

(11 citation statements)

References 25 publications

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“…[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 . [6,27] Our results also suggest that C impurity is the main impurity governing W source without the effect of ELMs, which is in agreement with the results shown in Ref. [12].…”

Section: Resultssupporting

confidence: 92%

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: 92%

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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“…Previous EAST experiments show that the substantially enhanced radiation in Ar seeding experiments is located further towards the core plasma than that with Ne seeding [21,22]. Because of the daily wall conditioning of the lithium (Li) coating, it is impossible to seed N 2 into EAST at present.…”

Section: Introductionmentioning

confidence: 99%

Comparison of divertor behavior and plasma confinement between argon and neon seeding in EAST

Yang

Wang

et al. 2021

Nucl. Fusion

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The exhaust of excessively high heat and particle fluxes on the divertor target is crucial for EAST long-pulse operation. In the recent EAST experiments, stable partial energy detachment around the upper outer strike point with H 98,y2 ∼ 1 was achieved with either Ne or Ar seeding from the upper outer divetor target in the upper single null configuration with ITER-like tungsten divertor. With either Ar or Ne seeding, the electron temperature around the upper outer strike point (T et,UOSP) was maintained at around 5 eV, the peak temperature of divertor target surface around the upper outer strike point (T div,UO) decreased significantly, and material sputtering was well suppressed. It was observed that there was less Ar seeding needed for partial energy detachment onset than Ne seeding, which shows that Ar is more efficient in the cooling of T et on the upper outer divertor than Ne. However, there was no detachment on the upper inner divertor with T et around strike point (T et,UISP) remaining >10 eV with either Ar or Ne seeding from the upper outer divertor. Accompanied with the disappearance of double peak phenomenon of ion flux density on the upper inner divertor target (j s,UI), the peak T div,UI around the strike point increased to around 300 °C. Although the heat flux on the upper inner divertor target (q t,UI) is still in the acceptable level, either Ar or Ne seeding only from the upper outer divertor target is not enough to protect the upper inner divertor target from sputtering under current EAST conditions. On the other hand, Ar seeding always causes confinement degradation in the partial energy detachment state. It was observed that there is a slight confinement improvement (∼10%) with Ne seeding, which may be due to density peaking, dilution effects and stabilization of the ion temperature gradient mode.

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“…The choice to consider pure Ar plasma is unusual for simulations with edge transport codes, where hydrogen (H) or deuterium (D) are commonly the main plasma species. Indeed, in Simulations of Ar plasmas in LPDs with SOLPS-ITER 3 tokamaks, Ar impurities are present in trace in the plasma as seeding for power dissipation purposes [35,36]. In PMI studies performed in LPDs, instead, Ar is often selected as the main plasma species [37,38].…”

Section: Introductionmentioning

confidence: 99%

Simulations of Argon plasmas in the linear plasma device GyM with the SOLPS-ITER code

Sala

Tonello

Uccello

et al. 2020

Plasma Phys. Control. Fusion

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Edge plasma codes, such as SOLPS, are widely used to study plasma transport in tokamaks scrape-off layers (SOL). The possibility to apply these codes to non hydrogenic plasmas and to linear plasma devices (LPDs) is gaining the interests of the fusion community. These facilities play a pivotal role in plasma-material interaction (PMI) studies for future fusion devices and may allow to test the code capabilities both in terms of geometry and simulated plasma species. In this contribution, we apply the SOLPS-ITER code for the simulations of Argon plasmas in the medium-flux linear machine GyM. A sensitivity scan over the pumping efficiency, transport coefficients and absorbed electron power was done, performing B2.5-EIRENE coupled simulations. A quantitative analysis of the different flux contributions is provided through the use of a twopoint modelling. Comparison with experiments shows a promising qualitative and quantitative agreement, with the sole exception of the simulated neutrals pressure. Dedicated EIRENE standalone simulations were performed to investigate this issue, also highlighting the role of neutral-neutral elastic collisions at high values of the puffing intensity.

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Influence of impurity seeding on the plasma radiation in the EAST tokamak

Cited by 10 publications

References 25 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*

Comparison of divertor behavior and plasma confinement between argon and neon seeding in EAST

Simulations of Argon plasmas in the linear plasma device GyM with the SOLPS-ITER code

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