Dynamics of fast ions during sawtooth oscillations in the TEXTOR tokamak measured by collective Thomson scattering

TitleDynamics of fast ions during sawtooth oscillations in the TEXTOR tokamak measured by collective Thomson scattering
Publication TypeJournal Article
Year of Publication2011
AuthorsS.K. Nielsen, M. Salewski, H. Bindslev, A. Burger, V. Furtula, M. Kantor, S.B Korsholm, H.R Koslowski, A. Kramer-Flecken, F. Leipold, F. Meo, P.K Michelsen, D. Moseev, J.W Oosterbeek, M. Stejner, E. Westerhof
JournalNuclear Fusion
Volume51
Issue6
Number6
Pagination063014
Date PublishedJun
Type of ArticleArticle
ISBN Number0029-5515
KeywordsBEHAVIOR, CRASHES, DISRUPTIONS, FLUCTUATIONS, FUSION PLASMAS, JET, REDISTRIBUTION, STABILIZATION, TEMPERATURE, WAVES
Abstract

Experimental investigations of sawteeth interaction with fast ions measured by collective Thomson scattering on TEXTOR are presented. Time-resolved measurements of localized 1D fast-ion distribution functions allow us to study fast-ion dynamics during several sawtooth cycles. Sawtooth oscillations interact strongly with the fast-ion population in a wide range of plasma parameters. Part of the ion phase space density oscillates out of phase with the sawtooth oscillation during hydrogen neutral beam injection (NBI). These oscillations most likely originate from fast hydrogen ions with energies close to the full injection energy. At lower energies passing fast ions in the plasma centre are strongly redistributed at the time of sawtooth collapse but no redistribution of trapped fast ions is observed. The redistribution of fast ions from deuterium NBI in the plasma centre is found to vary throughout velocity space. The reduction is most pronounced for passing ions. We find no evidence of inverted sawteeth outside the sawtooth inversion surface in the fast-ion distribution function.

DOI10.1088/0029-5515/51/6/063014
Division

FP

Department

PDG

PID

67db4fe34a6d341f7d3fa7d646132c7d

Alternate TitleNucl. Fusion

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