[Table of Contents]

Plasma and Fusion Research

Volume 2, S1097 (2007)

Regular Articles


Measurement of 3-D Mode Structure of the Edge Harmonic Oscillations in CHS using Beam Emission Spectroscopy
T. OISHI, S. KADO1), M. YOSHINUMA, K. IDA, T. AKIYAMA, T. MINAMI, K. NAGAOKA, A. SHIMIZU, S. OKAMURA and CHS group
National Institute for Fusion Science, Toki, Gifu 509-5292, Japan
1)
High Temperature Plasma Center, The University of Tokyo, Kashiwa, Chiba 277-8568, Japan
(Received 4 December 2006 / Accepted 27 April 2007 / Published 20 November 2007)

Abstract

The 3-D spatial structure - radial locality and poloidal/toroidal mode numbers - of the magnetohydrodynamic fluctuation called “edge harmonic oscillation (EHO)” in the compact helical system (CHS) was investigated using beam emission spectroscopy (BES) as the diagnostic method of the local density fluctuations and the magnetic probe array. We found two groups of harmonic oscillations in CHS, one with a frequency of 4.0 kHz and a harmonic located in the edge region of the normalized minor radius ρ = 0.95 near the rotational transform ι = 1 surface, and the other with a frequency of 3.5 kHz and a harmonic located in the core region ρ = 0.53 near the ι = 0.5 surface. The magnetic probe signals showed that the poloidal/toroidal mode numbers of the edge mode and the core mode were -1/1 and -2/1, respectively. They were consistent with the rotational transform of the magnetic field at the locations of those modes.


Keywords

density fluctuation, magnetohydrodynamics, edge harmonic oscillation, compact helical system, beam emission spectroscopy, H-mode, edge transport barrier

DOI: 10.1585/pfr.2.S1097


References

  • [1] C.M. Greenfield et al., Phys. Rev. Lett. 86, 4544 (2001).
  • [2] W. Suttrop et al., Plasma Phys. Control. Fusion 45, 1399 (2003).
  • [3] N. Oyama et al., Nucl. Fusion 45, 871 (2005).
  • [4] W. Suttrop et al., Nucl. Fusion 45, 721 (2005).
  • [5] T. Oishi et al., Proceedings of the 32nd European Physical Society Conference on Plasma Physics and Controlled Fusion, Tarragona, 2005 (European Physical Society, Geneva, 2005), Vol.29C, p. P4-94.
  • [6] T. Oishi et al., Nucl. Fusion 46, 317 (2006).
  • [7] K.H. Burrell et al., Phys. Plasmas 8, 2153 (2001).
  • [8] K.H. Burrell et al., Plasma Phys. Control. Fusion 44, A253 (2002).
  • [9] T. Oishi et al., Rev. Sci. Instrum. 75, 4118 (2004).
  • [10] T. Oishi et al., J. Plasma Fusion Res. 6, 449 (2004).
  • [11] R.J. Fonck et al., Rev. Sci. Instrum. 61, 3487 (1990).
  • [12] S. Sakakibara et al., Jap. J. Appl. Phys. 63, 4406 (1994).
  • [13] S. Okamura et al., J. Plasma Fusion Res. 79, 977 (2003).
  • [14] S. Okamura et al., Plasma Phys. Control. Fusion 46, A113 (2004).
  • [15] T. Minami et al., Plasma Fusion Res. 1, 032 (2006).
  • [16] T. Akiyama et al., Plasma Phys. Control. Fusion 48, 1683 (2006).
  • [17] M. Takeuchi et al., Plasma Phys. Control. Fusion 48, A277 (2006).
  • [18] S.P. Hirshman et al., Comput. Phys. Commun. 43, 143 (1986).
  • [19] T. Oishi et al., Phys. Plasmas 13, 104504 (2006).
  • [20] S. Kado et al., J. Nucl. Mat. 363-365, 522 (2007)
  • [21] S. Nishimura et al., Plasma Fusion Res. 2, 037 (2007)
  • [22] S. Kado et al., 21st IAEA Fusion Energy Conference Proceedings, EX/p8-1 (2006).

This paper may be cited as follows:

T. OISHI, S. KADO, M. YOSHINUMA, K. IDA, T. AKIYAMA, T. MINAMI, K. NAGAOKA, A. SHIMIZU, S. OKAMURA and CHS group, Plasma Fusion Res. 2, S1097 (2007).