Modification of Sawtooth Oscillations with ICRF Waves in the JET Tokamak

Journal Article · Fri Sep 28 00:00:00 EDT 2007 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.2800510· OSTI ID:21035885

Mantsinen, M J ^[1]; Alper, B; Buttery, R; Howell, D; Kiptily, V; Mayoral, M -L; Sharapov, S E ^[2]; Angioni, C; Mueck, A ^[1]; Coda, S; Graves, J P; Sauter, O ^[3]; Eriksson, L -G; Lennholm, M ^[4]; Hellsten, T; Johnson, T ^[5]; Ingesson, L C ^[6]; Nabais, F; Nave, F ^[7]; Noterdaeme, J -M ^[1]

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1. Max Planck IPP-EURATOM Assoziation, Boltzmann-Str. 2, D-85748 Garching (Germany)
2. EURATOM/UKAEA Fusion Association, Culham Science Centre, Abingdon Oxon 0X14 3DB (United Kingdom)
3. EURATOM Confederation Suisse, CRPP-EPFL, 1015 Lausanne (Switzerland)
4. Ass. EURATOM-CEA, CEA/DSM/DRFC, CEA-Cadarache, F-13108 St. Paul lez Durance (France)
5. Association EURATOM-VR, Fusion Plasma Physics, EES, KTH, SE-10044 Stockholm (Sweden)
6. EFDA Close Support Unit-Garching, Boltzmannstr. 2, D-85748 Garching (Germany)
7. Associacao EURATOM/IST, Centro de Fusao Nuclear, Instituto Superior Tecnico, Av Rovisco Pais, 1049-001 Lisbon (Portugal)

Methods of modifying sawtooth oscillations using waves in the ion cyclotron range of frequencies (ICRF) in the JET tokamak are presented. Examples of sawtooth stabilization by ICRF-accelerated high-energy ions are shown, including experiments with ICRF-acceleration of {sup 4}He-beam ions to simulate the effects of fusion born alpha particles. With high power ICRF heating in low-density plasmas, fast ion stabilization of sawteeth is lost and a new type of small-period and small-amplitude sawteeth appears. ICRF-induced radial pinch with toroidally asymmetric waves is found to be useful in affecting the radial profile of the ICRF-driven fast ion populations and thereby their influence on sawteeth. Ion cyclotron current drive (ICCD) applied close to the sawtooth inversion radius is effective in modifying the sawtooth period. The latest achievements include the successful application of ICCD to shorten the fast-ion-induced long-period sawteeth and thereby avoid triggering of neoclassical tearing modes (NTMs)

• OSTI ID: 21035885
• Journal Information: AIP Conference Proceedings, Vol. 933, Issue 1; Conference: 17. topical conference on radio frequency power in plasmas, Clearwater, FL (United States), 7-9 May 2007; Other Information: DOI: 10.1063/1.2800510; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA). Collaborations: JET-EFDA Task Force H; JET-EFDA Task Force M; JET-EFDA Contributors; ISSN 0094-243X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
ACCELERATION
ALPHA PARTICLES
AMPLITUDES
ASYMMETRY
HELIUM 4
ICR HEATING
ION CYCLOTRON-RESONANCE
IONS
JET TOKAMAK
NEOCLASSICAL TRANSPORT THEORY
PLASMA
PLASMA DENSITY
PLASMA JETS
PLASMA WAVES
RF SYSTEMS
SAWTOOTH OSCILLATIONS
STABILIZATION
TEARING INSTABILITY