[Table of Contents]

Plasma and Fusion Research

Volume 5, S2019 (2010)

Regular Articles

Study of Alfvén Eigenmodes in the TJ-II Stellarator
Alexander V. MELNIKOV, Leonid G. ELISEEV, Ruben JIMÉNEZ-GÓMEZ1), Enrique ASCASIBAR1), Carlos HIDALGO1), Alexander A. CHMYGA2), Takeshi IDO3), Sergey M. KHREBTOV2), Axel KÖNIES4), Alexander D. KOMAROV2), Alexander S. KOZACHEK2), Ivan A. KRASILNIKOV, Ludmila I. KRUPNIK2), Macarena LINIERS1), Sergey E. LYSENKO, Victor A. MAVRIN, Keinichi NAGAOKA3), Maria A. OCHANDO1), Jose L. DE PABLOS1), Maria A. PEDROSA1), Stanislav V. PERFILOV, Andrei I. SMOLYAKOV6), Yuri I. TASCHEV2), Mikhail V. UFIMTSEV7), Satoshi YAMAMOTO5) and Alexander I. ZHEZHERA2)
Institute of Tokamak Physics, RRC “Kurchatov Institute”, 123182, Moscow, Russia
1)
Asociación EURATOM-CIEMAT, 28040, Madrid, Spain
2)
Institute of Plasma Physics, NSC KIPT, 310108, Kharkov, Ukraine
3)
National Institute for Fusion Science, 322-6 Oroshi-cho, Toki 509-5292, Japan
4)
Max-Planck-Institut für Plasmaphysik, EURATOM-Association, D-17491, Greifswald, Germany
5)
Institute of Advanced Energy, Kyoto University, Kyoto, 611-0011, Japan
6)
University of Saskatchewan, 116 Science Place, Saskatoon SK S7N 5E2, Canada
7)
Department of Computational Mathematics and Cybernetics, Moscow State University, Russia
(Received 6 December 2009 / Accepted 13 April 2010 / Published 10 December 2010)

Abstract

Energetic ion driven Alfvén Eigenmodes (AEs) in the NBI-heated plasma at the TJ-II heliac were studied by Heavy Ion Beam Probing (HIBP) in the core, and by Langmuir and Mirnov probes (LP and MP) at the edge. HIBP observed the locally (∼ 1 cm) resolved AE at radii -0.5 < ρ < 0.9. The set of AE branches with low poloidal numbers (m < 8) was detected by MP. The most plausible candidates are global, helical and toroidal AEs. AEs on the density, electric potential and poloidal magnetic field oscillations were detected by HIBP at frequencies 50 kHz < fAE < 300 kHz with a high resolution (< 5 kHz). The amplitude of the AE potential oscillations δφAE ∼ 10 V was estimated. The MP and HIBP data have a high coherency at fAE. When the density rises, AE frequency is decreasing, fAE ∼ ne−1/2, but the cross-phase between the density and potential remains permanent. Poloidally resolved potential measurements by HIBP and LP shows high coherency and finite cross-phase at fAE, resulting in finite electric field δEpol. Depending on the cross-phase between δne and δEpol, AEs may bring small or significant contribution to the turbulent particle flux ΓE×B for the observed kθ < 3 cm−1.

Keywords

Alfvén eigenmode, turbulent flux, HIBP, TJ-II, NBI

DOI: 10.1585/pfr.5.S2019

Full Text

PDF format (2.8Mbytes) PDF Download

References

  • [1] W. W. Heidbrink et al., Phys. Plasmas 15, 055501 (2008).
  • [2] A. Weller et al., Phys. Plasmas 8, 931 (2001).
  • [3] K. Toi et al., Nucl. Fusion 40, 1349 (2000).
  • [4] T. Ido et al., Rev. Sci. Instrum. 79, 10F318 (2008).
  • [5] R. Jiménez-Gómez et al., accepted to Nucl. Fusion (2010).
  • [6] A. V. Melnikov et al., Proc. 36th EPS Conf. on Plasma Physics (Sofia, 2009) P4.186.
  • [7] S. E. Sharapov et al., Phys. Rev. Lett. 93, 165001 (2004).
  • [8] M. A. Van Zeeland et al., Phys. Rev. Lett. 97, 135001 (2006).
  • [9] A. J. H. Donné, A. V. Melnikov and G. Van Oost, Czech J. Phys. 55, 1077 (2002).
  • [10] A. V. Melnikov et al., Nucl. Fusion 50, 084023 (2010).
  • [11] Yu. N. Dnestrovskij, A. V. Melnikov, L. I. Krupnik and I. S. Nedzelskij, IEEE Trans. Plasma Sci. 22, 310 (1994).
  • [12] Yu. N. Dnestrovskij and A. V. Melnikov, Sov. J. Plasma Phys. 12, 393 (1986).
  • [13] A. V. Melnikov et al., Plasma Phys. Control. Fusion 48, S87 (2006).
  • [14] A. V. Melnikov et al., Fusion Sci. Technol. 51, 31 (2007).
  • [15] D. Yu. Eremin and A. Könies, Phys. Plasmas 17, 012108 (2010).
  • [16] E. J. Powers, Nucl. Fusion 14, 794 (1974).

This paper may be cited as follows:

Alexander V. MELNIKOV, Leonid G. ELISEEV, Ruben JIMÉNEZ-GÓMEZ, Enrique ASCASIBAR, Carlos HIDALGO, Alexander A. CHMYGA, Takeshi IDO, Sergey M. KHREBTOV, Axel KÖNIES, Alexander D. KOMAROV, Alexander S. KOZACHEK, Ivan A. KRASILNIKOV, Ludmila I. KRUPNIK, Macarena LINIERS, Sergey E. LYSENKO, Victor A. MAVRIN, Keinichi NAGAOKA, Maria A. OCHANDO, Jose L. DE PABLOS, Maria A. PEDROSA, Stanislav V. PERFILOV, Andrei I. SMOLYAKOV, Yuri I. TASCHEV, Mikhail V. UFIMTSEV, Satoshi YAMAMOTO and Alexander I. ZHEZHERA, Plasma Fusion Res. 5, S2019 (2010).