SOLPS-ITER modeling of divertor scenarios for EU-DEMO

Subba, F.; Coster, D.; Moscheni, M.; Siccinio, M.

doi:10.1088/1741-4326/ac1c85

Cited by 31 publications

(31 citation statements)

References 29 publications

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“…At least recent optimization study of EU-DEMO reactor by means of SOLPS-ITER simulation results in that operational regime with acceptable level of target heat loads and without notable fuel dilution may be achieved by conventional divertor radiation, that is, without the XPR. [27][28][29] Similar conclusion may be made from CFETR advanced divertor modelling. [30] Nevertheless, search for conditions required to achieve the XPR regime in reactors is underway.…”

Section: Introductionsupporting

confidence: 57%

Detached regime with highly radiating X‐point: Physics and modelling

Senichenkov

Rozhansky

Shtyrkhunov

et al. 2022

Contributions to Plasma Physics

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A possibility to operate with fully detached targets and highly radiating X-point was recently demonstrated on ASDEX Upgrade, JET, and DIII-D with intensive impurity seeding (N, Ne, Ar) and feedback control. Notable feature of such a regime is the radiated power fraction of up to 90% of discharge power inside the separatrix without a confinement degradation, or even with confinement improvement (in terms of H-factor), which leads to a full detachment of both targets. Therefore, this regime might be attractive for the next generation reactor scale tokamaks like DEMO or CFETR, where most of the power should be radiated. In the present report, the recent achievements in the understanding of such regime are reviewed. The effectiveness of divertor target shielding by different impurity gases is discussed, paying attention to its first ionization potential. SOLPS-ITER modelling results illustrating the impurity flow pattern are presented, and the importance of drift flows is demonstrated. The effect of the machine size on the effectiveness of the divertor shielding by impurity radiation is discussed. It is demonstrated that in bigger machines impurity radiation is better kept in the divertor and divertor asymmetry is less pronounced. As the seeding rate increases, both targets fully detach, and neutrals start to penetrate inside the separatrix above the X-point, leading to the plasma cooling there and to the formation of an observable localized radiation spot in the X-point vicinity.The cold zone above the X-point thus behaves as an energy sink like a divertor in conventional regime, so that the perpendicular decay length of perpendicular turbulent energy flow appears to be of the order of 𝜆 q of conventional divertor.During the formation of the radiating X-point a potential hill/well (depending on the direction of B × ∇B drift) is formed on perturbed closed flux surfaces, and the corresponding E × B drift vortex fluxes appear to give major contribution to the particle balance. SOLPS-ITER simulations show that the radial electric field significantly deviates from neoclassical formula and may even change sign (become positive). Thus, the zone of maximal poloidal rotation shear may shift inwards, which might be responsible for the inward shift of the transport barrier and for the confinement improvement. This effect is different to the discussed extension of peeling-ballooning stability boundary by intensive impurity injection, which

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Section: Introductionsupporting

confidence: 57%

Detached regime with highly radiating X‐point: Physics and modelling

Senichenkov

Rozhansky

Shtyrkhunov

et al. 2022

Contributions to Plasma Physics

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show abstract

“…It is worth to remind that only one type of radiating impurity was included in each modelled case and the power flux through the core boundary of computational domain is

200 MW

. This value could be reduced by the seeding of heavier impurity like it was described in References [6,7].…”

Section: Modelling Resultsmentioning

confidence: 99%

“…Toroidal magnetic field on magnetic axis is

4.9 T

, plasma current is

20 MA

{italicHe}^{2 +}

flux through the core boundary of computational mesh is

3.5 \times 10^{20} at / s

. To the contrary to vast majority of recently published works (see e.g., Reference [6,7]) moderate power scenario without high‐Z impurity like Kr, Xe was described. Only one type of radiating impurity is included—argon or neon.…”

Section: Introductionmentioning

confidence: 87%

Section: Introductionmentioning

confidence: 99%

“…Such a modelling has been done by several authors. Due to very long computational time, several simplifications were applied to achieve convergence: turning drifts and currents off [6,7] and fluid description of neutrals. [8] In this work, 1 GW EU-DEMO discharge scenario was modelled with SOLPS-ITER code [9,10] with full account of drifts and currents.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

SOLPS‐ITER EU‐DEMO modelling with drifts and kinetic neutrals

Vekshina

Korzueva

Rozhansky

et al. 2022

Contributions to Plasma Physics

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The edge transport modelling of 1 GW EU-DEMO burning plasma is performed by SOLPS-ITER transport code with kinetic neutrals and full drifts and currents switched on. The efficiency of Ar and Ne as a divertor radiant is compared for such a condition. It is found from simulations that both Ar and Ne are suitable to reduce the target heat loads below 5 MW∕m 2 , and to achieve similar profiles at the OMP and along targets, however, Ne seeding rate should be 4.5 times bigger than that of Ar. Analysis of impurity transport results in that Ar is better compressed in divertor than Ne. With both radiants up to 70% of power flux to the computational domain is irradiated, core Z eff does not exceed 2.5, core radiation is negligible (less than 8.5% of income power), neutral deuterium pressure in the private flux region is 20 Pa. However, the electron temperature along targets does not reduce below 15 eV in the far scrape-off layer, which may cause high level of tungsten sputtering.

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Discretization error estimation for EU‐DEMO plasma‐edge simulations using SOLPS‐ITER with fluid neutrals

Van Uytven,

Dekeyser,

Subba

et al. 2024

Contrib. Plasma Phys

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A grid refinement study is performed for mean‐field plasma boundary simulations with fluid neutrals in an EU‐DEMO geometry. In general, grid convergence of the simulations is achieved, with differences between the finest and second‐finest grid of <5% for the majority of the quantities of interest. The estimated discretization errors for the original 96 × 36 grid are mostly in the 4%–25% range. However, it is also shown that exceptions are possible due to the non‐linear nature of plasma boundary codes. Hence, it is advised to regularly perform grid refinement studies on subsets of cases.

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SOLPS-ITER modeling of divertor scenarios for EU-DEMO

Cited by 31 publications

References 29 publications

Detached regime with highly radiating X‐point: Physics and modelling

Detached regime with highly radiating X‐point: Physics and modelling

SOLPS‐ITER EU‐DEMO modelling with drifts and kinetic neutrals

Discretization error estimation for EU‐DEMO plasma‐edge simulations using SOLPS‐ITER with fluid neutrals

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