Validation of equilibrium tools on the COMPASS tokamak

Urbán, J.; Appel, L. C.; Artaud, J. F.; Faugeras, Blaise; Havlíček, J.; Komm, M.; Lupelli, I.; Peterka, M.

doi:10.1016/j.fusengdes.2015.06.132

Cited by 5 publications

(4 citation statements)

References 4 publications

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“…The ability to calculate plasma fluxes on main chamber structures, such as the baffle, is a strong asset for S2DE in the panorama of interpretative 2D transport models, especially if the focus is on plasma-wall interactions and core contamination studies. The S2DE mesh is based on the magnetic equilibrium for discharge #54067 for t = 8 s obtained with the real time plasma shape reconstruction tool VacTH [15,16]. For the simulation presented in this paper, the output of the VacTH calculation is modified to account for two experimental evidences.…”

Section: Model Setup and Assumptionsmentioning

confidence: 99%

“…The S2DE mesh is based on the magnetic equilibrium for discharge #54067 for t = 8 s obtained with the real time plasma shape reconstruction tool VacTH [12,13]. For the simulation presented in this paper, the output of the (a) Time traces for the WEST plasma discharge #54067: Ohmic power (black), lower hybrid current drive power (green), total heating power (red), power radiate in bulk plasma (blue), power losses due to magnetic ripple (gray), power entering the scrape-off layer (magenta); (b) time traces of the main plasma (red) and divertor (blue) line integrated density; the yellow shaded area corresponds to the VUV spectroscopy scan time interval.…”

Section: Model Setup and Assumptionsmentioning

confidence: 99%

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Interpretative transport modeling of the WEST boundary plasma: main plasma and light impurities

et al. 2020

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Understanding impurity transport in tokamak plasmas is crucial to control radiative losses and material migration in future magnetic fusion reactors. In this work we deploy the SolEdge2D-EIRENE code to model the boundary plasma in a WEST discharge, satisfactorily reproducing measurements of both upstream and divertor plasma conditions. The spatial distribution of oxygen, studied here as a representative light impurity, is compared to vacuum ultraviolet spectroscopy measurements acquired with an oscillating line of sight. The simulation captures a key feature of the experiment, namely a factor of 2 higher oxygen brightness in the inner divertor region compared to the outer one. This spatial asymmetry in oxygen concentration is interpreted by analyzing the balance of friction forces and thermal gradient forces that the light impurity exchanges with the main plasma.

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Section: Model Setup and Assumptionsmentioning

confidence: 99%

Section: Model Setup and Assumptionsmentioning

confidence: 99%

Interpretative transport modeling of the WEST boundary plasma: main plasma and light impurities

et al. 2020

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“…The measurements were performed during the steady-state phase of the discharge at a constant plasma current of 170 kA and a line-average electron density of 5×10 19 m −3 . The toroidal magnetic field was 1.15 T. The limiter on the low-field side is located at R=0.77 m. The reconstruction of the magnetic surfaces using the EFIT++ equilibrium code yields a position of the LCFS of 0.732±0.02 m [33]. Figure 3 presents floating potential data acquired by both LP.…”

Section: Plasma Parameters Results In L-mode Dischargesmentioning

confidence: 99%

Plasma potential and electron temperature evaluated by ball-pen and Langmuir probes in the COMPASS tokamak

Dimitrova

Popov

Adámek

et al. 2017

Plasma Phys. Control. Fusion

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The radial distributions of the main plasma parameters in the scrape-off-layer of the COMPASS tokamak are measured during L-mode and H-mode regimes by using both Langmuir and ball-pen probes mounted on a horizontal reciprocating manipulator. The radial profile of the plasma potential derived previously from Langmuir probes data by using the first derivative probe technique is compared with data derived using ball-pen probes. A good agreement can be seen between the data acquired by the two techniques during the L-mode discharge and during the H-mode regime within the inter-ELM periods. In contrast with the first derivative probe technique, the ball-pen probe technique does not require a swept voltage and, therefore, the temporal resolution is only limited by the data acquisition system. In the electron temperature evaluation, in the far scrape-off layer and in the limiter shadow, where the electron energy distribution is Maxwellian, the results from both techniques match well. In the vicinity of the last closed flux surface, where the electron energy distribution function is bi-Maxwellian, the ball-pen probe technique results are in agreement with the high-temperature components of the electron distribution only. We also discuss the application of relatively large Langmuir probes placed in parallel and perpendicularly to the magnetic field lines to studying the main plasma parameters. The results obtained by the two types of the large probes agree well. They are compared with Thomson scattering data for electron temperatures and densities. The results for the electron densities are compared also with the results from ASTRA code calculation of the electron source due to the ionization of the neutrals by fast electrons and the origin of the bi-Maxwellian electron energy distribution function is briefly discussed.

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“…The two magnetic plasma configurations used in these experiments are shown in figure 2 with the plasma magnetic equilibrium reconstruction of the magnetic surfaces performed by using the Equilibrium FIT++ code (EFIT) [17], plasma elongation 1.8. The first configuration, hereafter type 1, is the standard "small plasma" configuration.…”

Section: Langmuir Probe Measurements In the Divertor Region Of The Co...mentioning

confidence: 99%

Experimental observations of local plasma parameters in the COMPASS divertor in NBI-assisted L-mode plasmas

Dimitrova¹,

Popov²,

Havlíček³

et al. 2021

J. Inst.

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A: This paper presents an experimental characterization of the local plasma parameters in the COMPASS open divertor in deuterium, L-mode plasmas by means of Langmuir probes during neutral beam injection (NBI) heating. The effect of NBI heating of the core plasma on the local divertor plasma parameters is investigated under different plasma configurations and different directions of the magnetic field and plasma current for different line-averaged electron densities. At low line-averaged densities below 6 × 10 19 m −3 , a low NBI heating power level does not lead to any significant changes in the plasma parameters in the divertor region. It is also found that for a reversed magnetic field the influence of NBI in the divertor is stronger at higher line-averaged electron density and plasma current. In the divertor, the impact of the NBI heating is more pronounced at high delivered powers (above 𝑃 NBI = 320 kW) and line-averaged densities (above 7 × 10 19 m −3 ). The electron temperature and the floating potential at the outer target increases respectively with 10-50% and 100%, while the plasma potential in the inner divertor increases twofold. At a higher line-averaged density, the NBI heating affects the edge plasma, namely, the electron temperature in the midplane scrape-off layer and the heating moves toward the divertor. Thus, a twice as high electron temperature is observed in the divertor and a bi-Maxwellian electron energy distribution function arises. K: Plasma diagnostics -probes; Data processing methods; Ionization and excitation processes Deceased.

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Validation of equilibrium tools on the COMPASS tokamak

Abstract: International audienc

Cited by 5 publications

References 4 publications

Interpretative transport modeling of the WEST boundary plasma: main plasma and light impurities

Interpretative transport modeling of the WEST boundary plasma: main plasma and light impurities

Plasma potential and electron temperature evaluated by ball-pen and Langmuir probes in the COMPASS tokamak

Experimental observations of local plasma parameters in the COMPASS divertor in NBI-assisted L-mode plasmas

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