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

A. Huber*, M. Wischmeier, M. Bernert, S. Wiesen, S. Glöggler, S. Aleiferis, S. Brezinsek, G. Calabro, P. Carvalho, V. Huber, G. Sergienko, E. R. Solano, C. Giroud, M. Groth, S. Jachmich, Ch Linsmeier, G. F. Matthews, A. G. Meigs, Ph Mertens, M. SertoliS. Silburn, G. Telesca

*Corresponding author for this work

Research output: Contribution to journalConference articleScientificpeer-review

12 Citations (Scopus)

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.

Original languageEnglish
Article number014055
Number of pages7
JournalPhysica Scripta
VolumeT171
Issue number1
DOIs
Publication statusPublished - 1 Jan 2020
MoE publication typeA4 Conference publication
EventInternational Conference on Plasma-Facing Materials and Components for Fusion Applications - Eindhoven, Netherlands
Duration: 20 May 201924 May 2019
Conference number: 17

Keywords

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

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