Regular Articles

Full Text / References

Development of a Lithium Beam Probe and Measurement of Density Pedestal in JT-60U

Atsushi KOJIMA, Kensaku KAMIYA, Takaaki FUJITA, Hirotaka KUBO, Harukazu IGUCHI¹⁾, Naoyuki OYAMA, Takahiro SUZUKI, Yutaka KAMADA and the JT-60 Team

Japan Atomic Energy Agency, Naka, Ibaraki 311-0193, Japan

1)

National Institution of Fusion Science, Toki, Gifu 509-5292, Japan

(Received 16 July 2009 / Accepted 16 March 2010 / Published 28 April 2010)

Abstract

A lithium beam probe (LiBP) has been developed for the measurement of electron density profiles with highly spatial and temporal resolutions in JT-60U. Using an electron beam heating ion source with a capability of 10 mA extraction, a 5.5 mA beam has been injected to the plasmas. It corresponds to the equivalent neutral beam current of 2 mA. A spectrum width of the beam emission has been small enough to separate Zeeman splitting. By use of the LiBP, time evolutions of pedestal density profiles during type I and grassy edge localized modes (ELMs) have been obtained for the first time. After a type I ELM crash, the drop of the line-integrated density measured by an interferometer delays by 2 ms later than that of the pedestal density. Comparing the line-integrated density to the line integration of the edge density profile measured by the LiBP, it is found that the recovery from the type I ELM crash is correlated with the reduction of core plasma density. As for grassy ELMs, grassy ELMs have smaller density crashes than that of type I ELMs, which is mainly derived from the narrower ELM affected area.

Copyright (c) 2010 The Japan Society of Plasma Science and Nuclear Fusion Research

Keywords

JT-60U, tokamak, H mode, type I ELM, grassy ELM, edge density, LiBP (lithium beam probe)

DOI: 10.1585/pfr.5.015

Full Text

PDF format (1.3Mbytes)

References

• [1] H. Zohm, Plasma Phys. Control. Fusion 38, 105 (1996).
• [2] J.W. Connor, Plasma Phys. Control. Fusion 40, 531 (1998).
• [3] W. Suttrop, Plasma Phys. Control. Fusion 42, A1 (2000).
• [4] E.J. Doyle et al., Progress in the ITER Physics Basis Chapter 2, Nucl. Fusion 47, S18 (2007).
• [5] N. Oyama, Journal of Physics: Conference Series 123, 012002 (2008).
• [6] T.E. Evans et al., Phys. Rev. Lett. 92, 235003 (2004).
• [7] H. Urano et al., Phys. Rev. Lett. 95, 035003 (2005).
• [8] H. Urano et al., Nucl. Fusion 48, 045008 (2008).
• [9] K. Kamiya et al., Plasma Fusion Res. 2, 005 (2007).
• [10] N. Oyama et al., Plasma Phys. Control. Fusion 49, A249 (2007).
• [11] N. Oyama et al., Nucl. Fusion 45, 871 (2005).
• [12] D.M. Thomas et al., Rev. Sci. Instrum. 61, 3040 (1990).
• [13] Z.A. Pietrzyk et al., Plasma Phys. Control. Fusion 35, 1725 (1993).
• [14] E. Wolfrum et al., Rev. Sci. Instrum. 77, 033507 (2006).
• [15] A. Kojima et al., Rev. Sci. Instrum. 79, 093502 (2008).
• [16] B.W. Rice, Fusion. Eng. Des. 34-35, 135 (1997).
• [17] G. Matsunaga et al., Fusion. Eng. Des. 82, 207 (2007).
• [18] S. Sasaki et al., Rev. Sci. Instrum. 64, 1699 (1993).
• [19] N. Oyama et al., Nucl. Fusion 43, 1250 (2003).
• [20] N. Oyama et al., Nucl. Fusion 44, 582 (2004).
• [21] A. Kojima et al., Nucl. Fusion 49, 115008 (2009).

This paper may be cited as follows:

Atsushi KOJIMA, Kensaku KAMIYA, Takaaki FUJITA, Hirotaka KUBO, Harukazu IGUCHI, Naoyuki OYAMA, Takahiro SUZUKI, Yutaka KAMADA and the JT-60 Team, Plasma Fusion Res. 5, 015 (2010).