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- S. Briguglio
- Associazione EURATOM-ENEA , CR ENEA-Frascati, Via E. Fermi 45, 00044 Frascati (Rome), Italy
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- G. Fogaccia
- Associazione EURATOM-ENEA , CR ENEA-Frascati, Via E. Fermi 45, 00044 Frascati (Rome), Italy
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- G. Vlad
- Associazione EURATOM-ENEA , CR ENEA-Frascati, Via E. Fermi 45, 00044 Frascati (Rome), Italy
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- F. Zonca
- Associazione EURATOM-ENEA , CR ENEA-Frascati, Via E. Fermi 45, 00044 Frascati (Rome), Italy
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- K. Shinohara
- Japan Atomic Energy Agency , Naka, Ibaraki 311-0193, Japan
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- M. Ishikawa
- Japan Atomic Energy Agency , Naka, Ibaraki 311-0193, Japan
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- M. Takechi
- Japan Atomic Energy Agency , Naka, Ibaraki 311-0193, Japan
説明
<jats:p>The results of particle-in-cell simulations of a negative neutral beam heated Alfvén-mode experiment in the Japan Atomic Energy Research Institute Tokamak-60 Upgrade (JT-60U) [H. Ninomiya et al., Fusion Sci. Technol. 42, 7 (2002); A. Kitsunezaki et al., Fusion Sci. Technol. 42, 179 (2002)] are presented. They seem to match quite well the dynamics of the abrupt large-amplitude event (ALE) experimentally observed in the reference JT-60U discharge. The time scale and frequency spread of the ALE are well reproduced too. The issue of the weaker Alfvén fluctuation phase following the ALEs, characterized by fast frequency sweeping modes, is also investigated and an interpretation of the full JT-60U bursting-mode phenomenology is presented. Finally, the simulation tool is exploited by ad hoc synthetic diagnostics on the fast ion distribution function to get a deeper insight into the ALE nonlinear dynamics. The underlying fast-growing energetic particle mode saturates as resonant energetic ions are scattered out of the resonance region and displaced outwards. The radially displaced ions resonate with outer Alfvén modes and enhance their local drive, consistently with the “avalanche” paradigm for mode nonlinear dynamics and energetic ion transports.</jats:p>
収録刊行物
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- Physics of Plasmas
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Physics of Plasmas 14 (5), 055904-, 2007-04-03
AIP Publishing