Numerical modelling of the impact of leakage under divertor baffle in WEST

Yang, Hao; Ciraolo, Guido; Bucalossi, J.; Bufferand, Hugo; Fedorczak, N.; Tamain, P.; Falchetto, G.; Rivals, N.; Gunn, J.; Marandet, Y.; Pégouriè, B.; Vartanian, S.

doi:10.1016/j.nme.2022.101302

Cited by 5 publications

(2 citation statements)

References 23 publications

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“…The impact of divertor closure has been investigated experimentally and numerically in TCV, indicating that baffles strongly increase the neutral pressure in the divertor, and facilitate access to a colder divertor, promoting detachment at a lower core plasma density threshold [14][15][16][17][18]. This result is consistent with studies of divertor closure in multiple tokamak devices such as DIII-D [19][20][21][22][23][24][25], ASDEX-Upgrade [26], JET [27][28][29], EAST [30,31], JT-60U [32], and WEST [33].…”

Section: Introductionsupporting

confidence: 69%

Numerical study of divertor detachment in TCV H-mode scenarios

Yang,

Ciraolo,

Février

et al. 2023

Plasma Phys. Control. Fusion

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The effect of divertor closure and nitrogen seeding on the detachment process has been studied by performing 2D numerical simulations of TCV H-mode divertor scenarios with the SOLEDGE3X-EIRENE edge plasma transport code. The simulations reveal that, in the cases with only deuterium gas fuelling, detachment occurs at a similar level of divertor neutral pressure (≈ 0.76 Pa), despite the difference in divertor closure achieved by changing the length of the outer baffle. Nitrogen reduces the target temperature with little effect on the upstream density and momentum loss but drops the upstream pressure, leading to a decrease in the target particle flux and divertor neutral pressure. Furthermore, when the radiation front starts to move up from the outer target, the peak parallel heat flux level at the outer target remains approximately the same (≈ 2.3 MW/m2), regardless of whether it is a deuterium fuelling scan, a nitrogen seeding scan at a fixed fuelling rate, or a change in the length of the outer baffle. An empirical partial detachment qualifier calibrated on AUG experimental data was compared with the TCV simulations. The results show good agreement in detachment state prediction, indicating the potential of this detachment qualifier to be applied in devices of different sizes, emphasizing the combined influence of input power entering the divertor, neutral pressure, and the concentration and species of impurity in achieving divertor detachment.

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Section: Introductionsupporting

confidence: 69%

Numerical study of divertor detachment in TCV H-mode scenarios

Yang,

Ciraolo,

Février

et al. 2023

Plasma Phys. Control. Fusion

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“…This increase is coherent with the difference in plasma current with pulses at 300 kA with wider SOL for the He campaign in comparison to C4 in deuterium which was mainly at 500 kA. First comparison with edge modelling performed with SOLEDGE3X-EIRENE [18] on few pulses [19] showed that this difference between USN and LSN can be retrieved with edge modelling, more comparison will be performed in the future for different pulses of the studied database.…”

Section: Radiated and Sol Contribution Over The Pfcssupporting

confidence: 57%

Calorimetry measurement for energy balance and energy distribution in WEST for L-mode plasmas

Gaspar,

Gerardin,

Corre

et al. 2024

Nucl. Fusion

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The paper presents the energy balance of 602 pulses from four different experimental campaigns of the WEST tokamak. Different magnetic configuration has been studied with lower single null and upper single null configuration with deuterium or helium plasmas. The energy balance is closed with an imbalance of about 5% of the total injected energy for most of the campaigns and for the different magnetic configurations. The distribution over the whole machine is shown with the outer first wall receiving the most part of the energy due to its large surface area with about 30% of the total heat load, and the divertor with 25% due to the heat loads deposited by the convected power in the scrape off layer. Finally, the tomography inversion of the bolometry measurement allows to disentangle the contribution of the radiated and convected power in the energy absorbed by each type of PFC. Showing that in upper single null configuration about 63% of the available energy in the SOL is deposited in the upper divertor through convected heat loads, while in lower single null this value is spread over the lower divertor with 45% and the baffle and upper divertor with about 10% for both.

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Self‐organization of plasma edge turbulence in interaction with recycling neutrals

Quadri,

Tamain,

Marandet

et al. 2024

Contrib. Plasma Phys

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Experimental results from several tokamaks suggest a strong impact of divertor density regimes on turbulent transport in the edge plasma. Reciprocally, the change in transverse transport and SOL width affects the access to density regimes, making it a fundamental topic for heat exhaust issue. Such phenomenology is highly nonlinear and can only be approached quantitatively using numerical simulations treating turbulence and neutrals recycling physics self‐consistently. In this study, the SOLEDGE3X edge multi‐fluid code is used to investigate the mutual interaction between edge plasma turbulence and neutrals recycling. A fluid neutrals model based on the assumption of a charge‐exchange‐dominated plasma‐neutral interaction has been implemented. Two simulations in circular geometry are compared: one without neutrals, where the particle flux is driven by a constant in flux from the core region, and the other one with neutrals recycling included in which the particle input to the system is self‐consistently injected by a gas puff from the midplane. The presence of the neutrals triggers three types of perturbations on the plasma: a local and non‐axisymmetric one driven by the gas puff, a global perturbation affecting both profiles and turbulence properties in the whole domain, and a local one in the vicinity of the limiter where recycling occurs. The largest effect of the inclusion of self‐consistent neutrals recycling is a large‐scale reorganization of the plasma profiles and turbulence properties due to the dissociation of particle and energy fluxes. These effects are expected to be more important at higher densities regimes or in diverted configuration.

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Numerical modelling of the impact of leakage under divertor baffle in WEST

Cited by 5 publications

References 23 publications

Numerical study of divertor detachment in TCV H-mode scenarios

Numerical study of divertor detachment in TCV H-mode scenarios

Calorimetry measurement for energy balance and energy distribution in WEST for L-mode plasmas

Self‐organization of plasma edge turbulence in interaction with recycling neutrals

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