Fast-ion transport induced by Alfvén eigenmodes in the ASDEX Upgrade tokamak

Research output: Contribution to journalJournal article – Annual report year: 2011Researchpeer-review

  • Author: Garcia-Munoz, M.

    Max Planck Institute

  • Author: Classen, I.G.J.

    Dutch Institute for Fundamental Energy Research

  • Author: Geiger, B.

    Max Planck Institute

  • Author: Heidbrink, W.W.

    University of California at Irvine

  • Author: Van Zeeland, M.A.

    General Atomics

  • Author: Äkäslompolo, S.

    Aalto University

  • Author: Bilato, R.

    Max Planck Institute

  • Author: Bobkov, V.

    Max Planck Institute

  • Author: Brambilla, M.

    Max Planck Institute

  • Author: Conway, G.D.

    Max Planck Institute

  • Author: Graça, S. da

    Instituto de Plasmas e Fosao Nuclear – Laboratorio Associado

  • Author: Igochine, V.

    Max Planck Institute

  • Author: Lauber, Ph.

    Max Planck Institute

  • Author: Luhmann, N.

    University of California at Davis

  • Author: Maraschek, M.

    Max Planck Institute

  • Author: Meo, Fernando

    Plasma Physics and Technology Programme, Risø National Laboratory for Sustainable Energy, Technical University of Denmark

  • Author: Park, H.

    Pohang University of Science and Technology

  • Author: Schneller, M.

    Max Planck Institute

  • Author: Tardini, G.

    Max Planck Institute

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A comprehensive suite of diagnostics has allowed detailed measurements of the Alfvén eigenmode (AE) spatial structure and subsequent fast-ion transport in the ASDEX Upgrade (AUG) tokamak [1]. Reversed shear Alfvén eigenmodes (RSAEs) and toroidal induced Alfvén eigenmodes (TAEs) have been driven unstable by fast ions from ICRH as well as NBI origin. In ICRF heated plasmas, diffusive and convective fast-ion losses induced by AEs have been characterized in fast-ion phase space. While single RSAEs and TAEs eject resonant fast ions in a convective process directly proportional to the fluctuation amplitude, δB/B, the overlapping of multiple RSAE and TAE spatial structures and wave–particle resonances leads to a large diffusive loss, scaling as (δB/B)2. In beam heated discharges, coherent fast-ion losses have been observed primarily due to TAEs. Core localized, low amplitude NBI driven RSAEs have not been observed to cause significant coherent fast-ion losses. The temporal evolution of the confined fast-ion profile in the presence of RSAEs and TAEs has been monitored with high spatial and temporal resolution. A large drop in the central fast-ion density due to many RSAEs has been observed as qmin passes through an integer. The AE radial and poloidal structures have been obtained with unprecedented details using a fast SXR as well as 1D and 2D ECE radiometers. GOURDON and HAGIS simulations have been performed to identify the orbit topology of the escaping ions and study the transport mechanisms. Both passing and trapped ions are strongly redistributed by AEs.
Original languageEnglish
JournalNuclear Fusion
Issue number10
Pages (from-to)103013
Publication statusPublished - 2011
CitationsWeb of Science® Times Cited: No match on DOI

    Research areas

  • Fusion energy

ID: 5720448