Integrated modelling of the Globus-M tokamak plasma and a comparison with SOL width scaling

Senichenkov, I.; Gogoleva, A.; Vekshina, E. O.; Zadvitskiy, G.; Molchanov, P.; Rozhansky, V.; Voskoboynikov, S.; Хромов, Н. А.; Lepikhov, S.A.; Гусев, В. К.

doi:10.1088/0029-5515/55/5/053012

Cited by 6 publications

(10 citation statements)

References 17 publications

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“…Recent scaling laws for the SOL width for attached divertors developed for conventional tokamaks [37,38] showed the tendency of the SOL width to decrease with plasma current raise, which was confirmed on the Globus-M both by measurements and integrated plasma modelling using ASTRA and B2SOLPS5.2 codes [39,45]. The SOL width at the equatorial plane varies approximately as − I ~p 1 (or even stronger).…”

Section: Discussionmentioning

confidence: 71%

“…Since u || seems to be independent of plasma current and as the Pfirsch-Schlüter velocity in Globus-M is inversely proportional to the product L B T p , one would expect L I ~1/ T p l , which is an indirect confirmation of the inverse dependence of λ q on plasma current. A more detailed description of the modelling results can be found in [45].…”

Section: Sol Width Measurements and Integrated Modelling Of Edge Plasmamentioning

confidence: 99%

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Review of Globus-M spherical tokamak results

et al. 2015

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The first experiments on noninductive current drive (CD) using lower hybrid waves in a spherical tokamak are described. Waves at 2.45 GHz were launched by a 10 waveguide grill with 120° phase shift between neighbouring waveguides. The experimental results for a novel poloidal slowing-down scheme are described. The CD efficiency is found to be somewhat larger than that predicted theoretically whilst at the same time being somewhat less than that for standard tokamak lower hybrid CD. Geodesic acoustic modes (GAM) have been discovered in Globus-M. GAMs are localized 2-3 cm inside the separatrix. The GAM frequency agrees with theory. The mode structures of plasma density and magnetic field oscillation at the GAM frequency have been studied. Fast particle confinement during neutral beam injection has been investigated and numerically simulated. Alfvén instabilities excited by fast particles were detected by a toroidal Mirnov probe array. Their excitation conditions are discussed and the dynamics of fast ion losses induced by Alfvén eigenmodes is presented. Preliminary experiments on the isotopic effect influence on global confinement in the ohmic Nuclear Fusion

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Section: Discussionmentioning

confidence: 71%

Section: Sol Width Measurements and Integrated Modelling Of Edge Plasmamentioning

confidence: 99%

Review of Globus-M spherical tokamak results

et al. 2015

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“…As has been shown in that work, the L-H transition is accompanied by the density rise and formation of a steep gradient on the density profile near the separatrix. Ion temperature is significantly lower than electron temperature during ohmic H-mode, and the transport barrier does not appear in the ion heat conductivity profile [9].…”

Section: Modeling Principlesmentioning

confidence: 95%

“…The ion temperature profile was not always available on Globus-M, so T i boundary value was the arbitrary parameter. For those two discharges for which the coupling [9] to the 1D ASTRA transport code is available, its value was taken from the integrated modeling. For others, the T i core boundary level was chosen according to charge-exchanged fast neutral analysis.…”

Section: Modeling Principlesmentioning

confidence: 99%

Globus-M plasma edge modeling with B2SOLPS5.2 code

Vekshina

Senichenkov

Rozhansky

et al. 2016

Plasma Phys. Control. Fusion

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The edge plasma of five Globus-M discharges was modeled by the B2SOLPS5.2 code. Plasma current varied in 114-198 kA range, and all discharges were in the H-mode. The modeled scrape-off layer (SOL) width appeared to be inversely proportional to the plasma current. Such a relation is observed in many other tokamaks. Heat flux to the outer divertor target and radiation power was examined for these discharges. Radiation was found to be responsible for 40% of the energy loss. Energy flux to the low outer divertor target was about 1/3 of the energy loss in the single-null low X-point discharges.

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“…We also plan to perform a more systematic assessment of the compatibility of the impurity flux entering the separatrix with the plasma operation (e.g. by coupling SOLPS-ITER to ASTRA, see [63,64]) and to validate the erosion model, e.g. relying on experiments in linear plasma devices [13].…”

Section: Conclusion and Perspectivementioning

confidence: 99%

SOLPS-ITER simulations of a CPS-based liquid metal divertor for the EU DEMO: Li vs Sn

Nallo¹,

Mazzitelli²,

Moscheni³

et al. 2022

Nucl. Fusion

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In this work, we study the effect of installing a liquid metal divertor (LMD) using a capillary-porous structure in the EU DEMO tokamak within the same envelope of the baseline solid divertor. We used the SOLPS-ITER code to model the Scrape-Off Layer (SOL) plasma and neutrals, coupled to a target thermal model to enable the self-consistent calculation of the LM target erosion rate, and adopting a fluid neutral model for the sake of simplicity. First calculations considering only D and Li (or Sn) showed a significant reduction of the steady state target heat load with respect to simulations considering only D, thanks to vapor shielding. Nevertheless, the computed peak target heat flux (~31 MW/m2 and ~44 MW/m2 for Li and Sn, respectively) was still larger than/borderline to the power handling limit of the LMD concepts considered. Moreover, the impurity concentration in the pedestal - a proxy for the core plasma dilution/contamination - was computed to be above/close to tolerability limits suggested by previous COREDIV calculations. These results indicate that the operational window of an LMD for the EU DEMO, without any additional impurity seeding, might be too narrow, if it exists, and that Sn looks more promising than Li. A second set of calculations was then performed simulating Ar seeding in the SOL, to further reduce the target heat load, and consequently the metal erosion rate. It was found that the mitigation of the plasma heat load due to Ar radiation in the SOL effectively replaces the radiation associated to vapor shielding in front of the target, thus allowing to operate the LMD in a regime of low target erosion. The resulting operational window was found to be significantly wider, both in terms of tolerable peak target heat flux and of acceptable core plasma contamination.

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Integrated modelling of the Globus-M tokamak plasma and a comparison with SOL width scaling

Cited by 6 publications

References 17 publications

Review of Globus-M spherical tokamak results

Review of Globus-M spherical tokamak results

Globus-M plasma edge modeling with B2SOLPS5.2 code

SOLPS-ITER simulations of a CPS-based liquid metal divertor for the EU DEMO: Li vs Sn

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