[Table of Contents]

Plasma and Fusion Research

Volume 2, 023 (2007)

Rapid Communications

First Observation of RF-Induced Visible Light Fluctuations
Yuki TORII, Akira EJIRI1), Tetsuya MASUDA1), Takuya OOSAKO1), Makoto SASAKI2), Hiroshi TOJO1), Hideo NUGA2), Yoshiyuki SHIMADA1), Nobuyuki SUMITOMO2), Jiro TSUJIMURA1), Soichiro KAINAGA2), Junichi SUGIYAMA1) and Yuichi TAKASE1)
High Temperature Plasma Center, The University of Tokyo
1)
Graduate School of Frontier Sciences, The University of Tokyo
2)
Graduate School of Science, The University of Tokyo
(Received 30 March 2007 / Accepted 23 April 2007 / Published 1 June 2007)

Abstract

In order to detect rf modulation of visible light emitted from plasma, a high-speed photodiode measurement system was developed. The system is located outside the vacuum vessel of the TST-2 spherical tokamak and measures visible light emissions through a quartz window. A dedicated amplifier for the photodiode was made. Care was taken to reduce the rf pickup noise. The frequency spectrum of the light signal detected during high harmonic fast wave (HHFW) heating showed modulation by HHFW. This is the first measurement of visible light modulation induced by HHFW, and shows promise for measurement of the rf electric field in the plasma core.

Keywords

high harmonic fast wave, photodiode, density fluctuation, visible light modulation, spherical tokamak, TST-2

DOI: 10.1585/pfr.2.023

Full Text

PDF format (107Kbytes) PDF Download

References

  • [1] T.M. Biewer et al., Phys. Plasmas 12, 056108 (2005).
  • [2] T. Taniguchi et al., J. Plasma Fusion Res. SERIES 6, 410 (2004).
  • [3] Y. Takase et al., Nucl. Fusion 41, 1543 (2001).
  • [4] T. Yamada et al., to be published in Plasma Fusion Res., in Proc. of 16th International Toki Conference (Toki, Japan, December 5-8, 2006).

This paper may be cited as follows:

Yuki TORII, Akira EJIRI, Tetsuya MASUDA, Takuya OOSAKO, Makoto SASAKI, Hiroshi TOJO, Hideo NUGA, Yoshiyuki SHIMADA, Nobuyuki SUMITOMO, Jiro TSUJIMURA, Soichiro KAINAGA, Junichi SUGIYAMA and Yuichi TAKASE, Plasma Fusion Res. 2, 023 (2007).