Plasma and Fusion Research

Volume 2, 039 (2007)

Rapid Communications

Measurement of Single Pass Electron Cyclotron (EC) Absorption Using Transmitted Waves in Heliotron J

Kazunobu NAGASAKI, Takayuki TSUJI¹⁾, Masatoshi NOSAKU¹⁾, Nobuhide SHIMAZAKI¹⁾, Tohru MIZUUCHI, Hiroyuki OKADA, Shinji KOBAYASHI, Kinzo SAKAMOTO, Zhen FENG, Katsumi KONDO¹⁾, Masashi KANEKO¹⁾, Gen MOTOJIMA¹⁾, Shinya WATANABE¹⁾, Alvaro CAPPA²⁾ and Fumimichi SANO

Institute of Advance Energy, Kyoto University
1): Graduate School of Energy Science, Kyoto University
2): Laboratorio Nacional de Fusión, EURATOM-CIEMAT

(Received 28 June 2007 / Accepted 17 July 2007 / Published 2 August 2007)

Abstract

Single pass absorption of second-harmonic EC waves propagating obliquely to the magnetic field has been studied in Heliotron J. Two orthogonal signals of transmitted high power EC waves are measured to estimate the single pass absorption rate. The experimental results agree well with ray tracing calculation results based on a linear absorption theory under the condition that the refraction effect is not strong, n_e/n_c < 0.3 (n_c is a cut-off density of second-harmonic X-mode), that is, the waves reach the diagnostic port.

Keywords

electron cyclotron absorption, microwave transmission, oblique propagation, absorption efficiency, wave polarization, Heliotron J

DOI: 10.1585/pfr.2.039

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References

[1] F. Sano et al., Nucl. Fusion 45, 1557 (2005).
[2] H. Shidara et al., Fusion Sci. Technol. 45, 41 (2004).
[3] K. Nagasaki et al., Nucl. Fusion 45, 13 (2005).
[4] K. Nagasaki et al., Int. J. Infrared Millim. Waves 20, 823 (1999).
[5] H. Shidara et al., J. Plasma Fusion Res. 81, 48 (2005).

This paper may be cited as follows:

Kazunobu NAGASAKI, Takayuki TSUJI, Masatoshi NOSAKU, Nobuhide SHIMAZAKI, Tohru MIZUUCHI, Hiroyuki OKADA, Shinji KOBAYASHI, Kinzo SAKAMOTO, Zhen FENG, Katsumi KONDO, Masashi KANEKO, Gen MOTOJIMA, Shinya WATANABE, Alvaro CAPPA and Fumimichi SANO, Plasma Fusion Res. 2, 039 (2007).