Peculiarity of highly radiating multi-impurity seeded H-mode plasmas on JET with ITER-like wall

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A4 Artikkeli konferenssijulkaisussa
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Date

2020-01-01

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Department of Applied Physics

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en

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7

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Physica Scripta, Volume T171, issue 1

Abstract

On JET with fully metallic first wall, highly radiative conditions with N2, Ne and Ar as well as their mixture as radiators are approached in high density H-mode plasmas. The confinement increases from H 98(y,2) = 0.65 in unseeded pulses with γ rad ∼ 30% to a value of H 98(y,2) = 0.75 at γ rad ∼ 50% with N2 injection. A degradation of the pedestal profile is compensated by steeper core n e and T e profiles. Further increase of γ rad with increase of the N2 seeding rate leads to a moderate confinement degradation which can be avoided by applying of combined impurity seeding. The enhancement of the plasma performance for the radiation fractions beyond 55% with the maximum value of H 98(y,2) = 0.78 is reached with combined N2 + Ne and N2 + Ar impurity injections. The observed intense, strongly localized radiation at the X-point inside the confined plasma in the scenarios with the highest radiated power fraction is interlinked to complete divertor detachment. In the JET-ILW, the X-point radiation is stable, reproducible and reversible.

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| openaire: EC/H2020/633053/EU//EUROfusion

Keywords

Detachment, Divertors, Impurities in plasmas, Power exhaust, Radiation, Tokamaks

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DOI

10.1088/1402-4896/ab5753

Citation

Huber, A, Wischmeier, M, Bernert, M, Wiesen, S, Glöggler, S, Aleiferis, S, Brezinsek, S, Calabro, G, Carvalho, P, Huber, V, Sergienko, G, Solano, E R, Giroud, C, Groth, M, Jachmich, S, Linsmeier, C, Matthews, G F, Meigs, A G, Mertens, P, Sertoli, M, Silburn, S & Telesca, G 2020, 'Peculiarity of highly radiating multi-impurity seeded H-mode plasmas on JET with ITER-like wall', Physica Scripta, vol. T171, no. 1, 014055. https://doi.org/10.1088/1402-4896/ab5753

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https://urn.fi/URN:NBN:fi:aalto-202102262131

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[article-cris] Perustieteiden korkeakoulu / SCI