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Title: Particle simulation of bursting Alfven modes in JT-60U

Abstract

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.

Authors:
; ; ; ; ; ;  [1];  [2]
  1. Associazione EURATOM-ENEA, CR ENEA-Frascati, Via E. Fermi 45, 00044 Frascati (Rome) (Italy)
  2. (Japan)
Publication Date:
OSTI Identifier:
20975032
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 14; Journal Issue: 5; Other Information: DOI: 10.1063/1.2710208; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
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

Citation Formats

Briguglio, S., Fogaccia, G., Vlad, G., Zonca, F., Shinohara, K., Ishikawa, M., Takechi, M., and Japan Atomic Energy Agency, Naka, Ibaraki 311-0193. Particle simulation of bursting Alfven modes in JT-60U. United States: N. p., 2007. Web. doi:10.1063/1.2710208.
Briguglio, S., Fogaccia, G., Vlad, G., Zonca, F., Shinohara, K., Ishikawa, M., Takechi, M., & Japan Atomic Energy Agency, Naka, Ibaraki 311-0193. Particle simulation of bursting Alfven modes in JT-60U. United States. doi:10.1063/1.2710208.
Briguglio, S., Fogaccia, G., Vlad, G., Zonca, F., Shinohara, K., Ishikawa, M., Takechi, M., and Japan Atomic Energy Agency, Naka, Ibaraki 311-0193. Tue . "Particle simulation of bursting Alfven modes in JT-60U". United States. doi:10.1063/1.2710208.
@article{osti_20975032,
title = {Particle simulation of bursting Alfven modes in JT-60U},
author = {Briguglio, S. and Fogaccia, G. and Vlad, G. and Zonca, F. and Shinohara, K. and Ishikawa, M. and Takechi, M. and Japan Atomic Energy Agency, Naka, Ibaraki 311-0193},
abstractNote = {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.},
doi = {10.1063/1.2710208},
journal = {Physics of Plasmas},
number = 5,
volume = 14,
place = {United States},
year = {Tue May 15 00:00:00 EDT 2007},
month = {Tue May 15 00:00:00 EDT 2007}
}