Fast-ion losses induced by ACs and TAEs in the ASDEX Upgrade tokamak

TitleFast-ion losses induced by ACs and TAEs in the ASDEX Upgrade tokamak
Publication TypeJournal Article
Year of Publication2010
AuthorsM. García-Muñoz, N. Hicks, R. van Voornveld, I.G.J. Classen, R. Bilato, V. Bobkov, M. Brambilla, M. Bruedgam, H.U Fahrbach, V. Igochine, S. Jaemsae, M. Maraschek, K. Sassenberg
JournalNuclear Fusion
Volume50
Number8
Pagination7
Date PublishedAug
Type of ArticleProceedings Paper
ISBN Number0029-5515
Accession NumberISI:000280505800005
KeywordsALFVEN-WAVE INSTABILITY, EIGENMODES, JET, MODES, NUMERICAL-SIMULATION, PARTICLE LOSS, PLASMAS, TRANSPORT
Abstract

The phase-space of convective and diffusive fast-ion losses induced by shear Alfven eigenmodes has been characterized in the ASDEX Upgrade tokamak. Time-resolved energy and pitch-angle measurements of fast-ion losses correlated in frequency and phase with toroidal Alfven eigenmodes (TAEs) and Alfven cascades (ACs) have allowed to identify both loss mechanisms. While single ACs and TAEs eject resonant fast-ions in a convective process, the overlapping of AC and TAE spatial structures leads to a large fast-ion diffusion and loss. The threshold for diffusive fast-ion losses depends on the ion energy (gyroradius). Diffusive fast-ion losses with gyroradius approximate to 70 mm have been observed with a single TAE for local radial displacements of the magnetic field lines larger than approximate to 2 mm. Multiple frequency chirping ACs cause an enhancement of the diffusive losses. The ACs and TAEs radial structures have been reconstructed by means of cross-correlation techniques between the fast-ion loss detector and the electron cyclotron emission radiometer.

URL<Go to ISI>://000280505800005
Division

Fusion Physics

PID

9f07fd57f3b5ae0080d101737aee6a70

Alternate TitleNucl. Fusion

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