Investigation of the influence of divertor recycling on global plasma confinement in JET ITER-like wall

P. Tamain*, E. Joffrin, H. Bufferand, Aaro Järvinen, S. Brezinsek, G. Ciraolo, E. Delabie, L. Frassinetti, C. Giroud, M. Groth, B. Lipschultz, P. Lomas, S. Marsen, S. Menmuir, M. Oberkofler, M. Stamp, S. Wiesen, JET-EFDA contributors

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

21 Citations (Scopus)

Abstract

Abstract The impact of the divertor geometry on global plasma confinement in type I ELMy H-mode has been investigated in the JET tokamak equipped with ITER-Like Wall. Discharges have been performed in which the position of the strike-points was changed while keeping the bulk plasma equilibrium essentially unchanged. Large variations of the global plasma confinement have been observed, the H98 factor changing from typically 0.7 when the outer strike-point is on the vertical or horizontal targets to 0.9 when it is located in the pump duct entrance. Profiles are mainly impacted in the pedestal but core gradient lengths, especially for the density, are also modified. Although substantial differences are observed in the divertor conditions, none seem to correlate directly with the confinement. Modelling with the EDGE2D-EIRENE and SOLEDGE2D-EIRENE transport codes exhibits differences in the energy losses due to neutrals inside the separatrix, but orders of magnitude are too low to explain simply the impact on the confinement.

Original languageEnglish
Article number48752
Pages (from-to)450-454
Number of pages5
JournalJournal of Nuclear Materials
Volume463
DOIs
Publication statusPublished - 22 Jul 2015
MoE publication typeA1 Journal article-refereed

Funding

This work, supported by the European Communities under the contract of Association between EURATOM and CEA, was carried out within the framework of the European Fusion Development Agreement. The views and opinions expressed herein do not necessarily reflect those of the European Commission. Computations have been performed at the Mésocentre d’Aix-Marseille Université.

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