Impact of the ITER-like wall on divertor detachment and on the density limit in the JET tokamak

TitleImpact of the ITER-like wall on divertor detachment and on the density limit in the JET tokamak
Publication TypeJournal Article
Year of Publication2013
AuthorsA. Huber, S. Brezinsek, M. Groth, P.C de Vries, V. Riccardo, G.J van Rooij, G. Sergienko, G. Arnoux, A. Boboc, P. Bilkova, G. Calabro, M. Clever, J.W Coenen, M.NA Beurskens, T. Eich, S. Jachmich, M. Lehnen, E. Lerche, S. Marsen, G.F Matthews, K. McCormick, A.G Meigs, P. Mertens, V. Philipps, J. Rapp, U. Samm, M. Stamp, M. Wischmeier, S. Wiesen
JournalJournal of Nuclear Materials
Volume438, Supplement
PaginationS139 - S147

L-mode and H-mode density limits with the ITER-like wall (ILW) have been investigated in the recent experimental campaign and compared with experiments in the JET carbon material configuration. The density limit is up to 40% higher in the JET-ILW than in the JET-CFC machine. This is linked to the formerly higher radiation fraction and, correspondingly, to earlier divertor detachment in the JET-CFC. In the ILW configuration, the discharge demonstrates a stable operation with a completely detached outer divertor in L- and H-mode. In contrary to the well-known “heating power independent” Greenwald limit, the L-mode densities limit increases moderately with rising heating power ( ∼ P heat 0.4 ) independently of the wall material. The H–L transition constitutes an effective undisruptive density limit for an H-mode plasma. Detachment itself does not trigger the H–L back transition and does not present a limit on plasma density. In the range of neutral beam heating 8–10.5 MW, no dependence of the H-mode density limit on the heating power was observed.







Alternate TitleJ. Nucl. Mater.

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