Hybrid H-mode scenario with nitrogen seeding and type III ELMs in JET

TitleHybrid H-mode scenario with nitrogen seeding and type III ELMs in JET
Publication TypeJournal Article
Year of Publication2008
AuthorsY. Corre, E. Joffrin, P. Monier-Garbet, Y. Andrew, G. Arnoux, M. Beurskens, S. Brezinsek, M. Brix, R. Buttery, I. Coffey, K. Crombe, E. de la Luna, R. Felton, C. Giroud, S. Hacquin, J. Hobirk, A. Huber, F. Imbeaux, S. Jachmich, M. Kempenaars, X. Litaudon, H. Leggate, T. Loarer, G. Maddison, E. Rachlew, J. Rapp, O. Sauter, A. Savchkov, G. Telesca, A. Widdowson, K.D Zastrow, O. Zimmermann
JournalPlasma Physics and Controlled Fusion
Volume50
Number11
Pagination20
Date PublishedNov
Type of ArticleArticle
ISBN Number0741-3335
Accession NumberISI:000260311700012
KeywordsASDEX-UPGRADE, CONFINEMENT, DIII-D, EDGE, GAS BOX DIVERTOR, HIGH-DENSITY, INTEGRATED SCENARIO, JOINT EUROPEAN TORUS, STATE ADVANCED SCENARIOS, THOMSON SCATTERING
Abstract

The performance of the 'hybrid' H-mode regime (long pulse operation with high neutron fluency) has been extensively investigated in JET during the 2005-2007 experimental campaign up to normalized pressure beta(N) = 3, toroidal magnetic field B-t = 1.7T, with type I ELMs plasma edge conditions. The optimized external current drive sources, self-generated non-inductive bootstrap current and plasma core stability properties provide a good prospect of achieving a high fusion gain at reduced plasma current for long durations in ITER. One of the remaining issues is the erosion of the divertor target plates associated with the type I ELM regime. A possible solution could be to operate with a plasma edge in the type III ELM regime (reduced transient and stationary heat loads) obtained with impurity seeding. An integrated hybrid type III ELM regime with a normalized pressure beta(N) = 2.6 (PNBI similar to 20-22 MW) and a thermal confinement factor of H-98* 98(y, 2) similar to 0.83 has been recently successfully developed on JET with nitrogen seeding. This scenario shows good plasma edge condition (compatible with the future ITER-like wall on JET) and moderate MHD activity. In this paper, we report on the experimental development of the scenario (with plasma current I-p = 1.7MA and magnetic field B-t = 1.7T) and the trade-off between heat load reduction at the target plates and global confinement due to nitrogen seeding and type III ELM working conditions.

URL<Go to ISI>://000260311700012
Division

Fusion Physics

PID

05ed723ff0cf9e79390d0257e9be4d4d

Alternate TitlePlasma Phys. Control. Fusion

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