Particle simulation of bursting Alfven modes in JT-60U

Journal Article · Tue May 15 04:00:00 EDT 2007 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.2710208· OSTI ID:20975032

Briguglio, S; Fogaccia, G; Vlad, G; Zonca, F; Shinohara, K; Ishikawa, M; Takechi, M ^[1]

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1. Associazione EURATOM-ENEA, CR ENEA-Frascati, Via E. Fermi 45, 00044 Frascati (Rome) (Italy)

The results of particle-in-cell simulations of a negative neutral beam heated Alfven-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., ibid. 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 Alfven 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 Alfven modes and enhance their local drive, consistently with the ''avalanche'' paradigm for mode nonlinear dynamics and energetic ion transports.

• OSTI ID: 20975032
• Journal Information: Physics of Plasmas, Journal Name: Physics of Plasmas Journal Issue: 5 Vol. 14; ISSN PHPAEN; ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
ALFVEN WAVES
BEAMS
DISTRIBUTION FUNCTIONS
FLUCTUATIONS
HEATING
JAERI
JT-60U TOKAMAK
NONLINEAR PROBLEMS
PLASMA
PLASMA BEAM INJECTION
PLASMA CONFINEMENT
PLASMA SIMULATION
TAIL IONS