Simulation study of the influence on the tungsten concentration due to the cross-field transport in the scrape-off layer

Xu, Yuchen; Xu, Guoliang; Mao, Shifeng; Ye, Minyou

doi:10.1088/1361-6587/ac11b3

Cited by 5 publications

(3 citation statements)

References 52 publications

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“…This experimental observation is consistent with the simulation results in Refs. [20,21]. Due to the increase of particle flux onto the target with Ne seeding as shown in Fig.…”

Section: Effect Of Ne Seeding On Divertor W Sputteringmentioning

confidence: 99%

Experimental investigation on divertor tungsten sputtering with neon seeding in ELMy H-mode plasma in EAST tokamak

Ye¹,

Ding²,

Li³

et al. 2022

Chinese Phys. B

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Neon (Ne) seeding is used to cool the edge plasma by radiation to protect the divertor tungsten (W) target in the Experimental Advanced Superconducting Tokamak (EAST). The W sputtering in the outer divertor target with Ne seeding is assessed by the divertor visible spectroscopy system. It is observed that the W sputtering flux initially increases with Ne concentration in the divertor despite the decreasing plasma temperature. After reaching a maximum around 25 eV, the W sputtering rate starts to decrease, presenting a suppression effect. The effect on the divertor W sputtering flux and yield due to the competition between the increase of the Ne concentration and the decrease of the plasma temperature is discussed. The results show that enough Ne seeding is essential to effectively reduce the electron temperature and thus to suppress W sputtering. Moreover, ELM suppression is observed when Ne and W impurities enter the core plasma, which could be correlated to the enhanced turbulence transport in the pedestal.

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“…This experimental observation is consistent with the simulation results in Refs. [20,21]. Due to the increase of particle flux onto the target with Ne seeding as shown in Fig.…”

Section: Effect Of Ne Seeding On Divertor W Sputteringmentioning

confidence: 99%

Experimental investigation on divertor tungsten sputtering with neon seeding in ELMy H-mode plasma in EAST tokamak

Ye¹,

Ding²,

Li³

et al. 2022

Chinese Phys. B

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“…Thus, the effect of E × B drift on W transport can be understood by studying its influence on Γ W in detail. It should be noted that if D ⊥,W is much lower than the typical value of 1 m 2 s −1 used in this work, the flow pattern discussed below will be modified [33,79].…”

Section: Statistics Of the Effects Of E × B Drift On The Three Stages...mentioning

confidence: 91%

“…Therefore, it is of great importance to understand the transport of W impurities in the scrape-off layer (SOL), which determines the source of the tungsten contamination inside the confined plasma. Many efforts have been conducted on this subject for various existing tokamaks, such as EAST [19][20][21][22], DIII-D [23,24], JET [25][26][27], and ASDEX-Upgrade [28], and for future fusion reactors, such as ITER [29,30], CFETR [31][32][33], and DEMO [34].…”

Section: Introductionmentioning

confidence: 99%

Simulation study of the influence of E× B drift on tungsten impurity transport in the scrape-off layer

Guo,

Xu,

Mao

et al. 2023

Nucl. Fusion

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Future fusion reactors such as ITER have adopted tungsten (W) as the plasma-facing materials (PFMs) in the divertor region. It is crucial to keep the W concentration in the core plasma at an extremely low level. Great efforts have been put forward on understanding the W transport in the scrape-off layer (SOL), which is related to the source of the core W contamination. In this work, the influence of E×B drift on the W impurity transport in the SOL is studied by numerical simulations for a model case based on EAST upper single-null configuration with high recycling divertor plasma. The W transport is simulated using DIVIMP on the background plasma obtained from SOLPS-ITER simulation including drifts. The E×B drift of the W ions is introduced according to the background electric field. Therefore, both the direct E×B drift effect of W ion itself and the indirect effect via background plasma on the W transport process in the SOL can be studied. We focus on the influence on the flux of W impurities entering confined plasma across the last closed flux surface Γenter, which is expected to be proportional to the core W concentration. It is found that Γenter is mainly from the outer (inner) target under favorable (unfavorable) toroidal field BT, and can be increased by more than one order of magnitude compared with the case without drifts. It reflects the significant influence of E×B drift effects. The detailed effects due to the background plasma and the poloidal and radial E×B drift of W ion, as well as the related mechanisms, are analyzed for the three stages of W transport in the SOL, including the effective sputtering from the target, the leakage from the divertor and the entry into the confined plasma.

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Simulation study of the influence of the cross‐field anomalous diffusion on the tungsten impurity transport in the scrape‐off layer with activated drifts

Guo,

Xu,

Mao

et al. 2024

Contrib. Plasma Phys

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Tungsten (W) impurity eroded from the divertor target can degrade the confinement performance of future fusion reactors. The mechanism of the effect of E × B drift on the W transport in the scrape‐off layer (SOL) was investigated with a fixed cross‐field anomalous particle diffusion coefficient for W ions (D⊥,W) of 1 m2s−1 in our previous simulation work, which indicates that the W flux entering the confined region (Γenter) and mean W concentration in the confined region () can be increased by more than one order of magnitude by drifts. In this work, the influence of the cross‐field anomalous diffusion on the W transport in the SOL is further investigated. The basic flow pattern of the W ion flux (ΓW) keeps when D⊥,W varying from 0.5 to 3 m2s−1, and Γenter mainly comes from the hotter divertor region. Results show that D⊥,W value affects the W leakage from divertor region and entry into confined region. Therefore, Γenter and both decrease with increasing D⊥,W. Mechanisms for cases w/wo drifts are compared.

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Simulation study of the influence on the tungsten concentration due to the cross-field transport in the scrape-off layer

Cited by 5 publications

References 52 publications

Experimental investigation on divertor tungsten sputtering with neon seeding in ELMy H-mode plasma in EAST tokamak

Experimental investigation on divertor tungsten sputtering with neon seeding in ELMy H-mode plasma in EAST tokamak

Simulation study of the influence of E× B drift on tungsten impurity transport in the scrape-off layer

Simulation study of the influence of the cross‐field anomalous diffusion on the tungsten impurity transport in the scrape‐off layer with activated drifts

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