Optimization of pellet scenarios for long pulse fuelling to high densities at JET

TitleOptimization of pellet scenarios for long pulse fuelling to high densities at JET
Publication TypeJournal Article
Year of Publication2002
AuthorsP.T Lang, B. Alper, L.R Baylor, M. Beurskens, J.G Cordey, R. Dux, R. Felton, L. Garzotti, G. Haas, L.D Horton, S. Jachmich, T.TC Jones, P.J Lomas, A. Lorenz, M. Maraschek, H.W Miller, J. Ongena, J. Rapp, M. Reich, K.F Renk, R. Sartori, G. Schmidt, M. Stamp, W. Suttrop, E. Villedieu
JournalNuclear Fusion
Volume42
Number4
Pagination388-402
Date PublishedApr
Type of ArticleArticle
ISBN Number0029-5515
Accession NumberISI:000175742700005
KeywordsASDEX UPGRADE, DISCHARGES, DRIFT, INJECTION, LAUNCH, NEOCLASSICAL TEARING MODES, OPERATION, PERFORMANCE, TOKAMAK PLASMAS
Abstract

Pellet injection was investigated for its fuelling capability to high densities in ELMy H mode discharges at JET. Applying the high field side launch system, optimized refuelling scenarios were developed on the basis of conventional discharge configurations with I-p = 2.5 MA, B-t = 2.4 T, averaged triangularity (delta) approximate to 0.34 and mainly neutral beam heating at a level of approximately 17 MW. The accessible operational range was extended with respect to gas puff refuelling by the use of pellet injection. For example, H mode conditions could be maintained at densities beyond the Greenwald level. Plasma energy confinement was observed to become density independent at high densities. Deep pellet particle deposition made possible the uncoupling of edge and core density, allowing more peaked density profiles. When confinement deterioration due to pellet triggered MHD activity or parasitic pellet borne gas was avoided in appropriate pulse schedules, an enhanced particle inventory was achieved while maintaining the plasma pressure profile. In a technical assessment it was found that there is still room for further enhancement of the injection scenario by improved adaptation to high density plasma operation.

URL<Go to ISI>://000175742700005
Division

Fusion Physics

Department

Tokamak physics

PID

1421a6c4436c95928b481d5e864c5873

Alternate TitleNucl. Fusion

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