[Table of Contents]

Plasma and Fusion Research

Volume 9, 3402040 (2014)

Regular Articles

Identification of Waves by RF Magnetic Probes during Lower Hybrid Wave Injection Experiments on the TST-2 Spherical Tokamak
Takahiro SHINYA, Akira EJIRI, Yuichi TAKASE, Takuma WAKATSUKI, Takuya OOSAKO, Naoto TSUJII, Hidetoshi KAKUDA, Hirokazu FURUI, Junichi HIRATSUKA, Takuma INADA, Kazuhiro IMAMURA, Keishun NAKAMURA, Ayaka NAKANISHI, Masateru SONEHARA, Hiro TOGASHI, Shintaro TSUDA, Takashi YAMAGUCHI, Hiroshi KASAHARA1), Kenji SAITO1), Tetsuo SEKI1), Fujio SHIMPO1), Yoshihiko NAGASHIMA2), Osamu WATANABE2) and Takuma YAMADA2)
The University of Tokyo, Kashiwa 277-8561, Japan
1)
National Institute for Fusion Science,Toki 509-5292, Japan
2)
Kyushu University, 6-1 Kasuga-koen, Kasuga, Fukuoka 816-8580, Japan
(Received 16 December 2013 / Accepted 3 March 2014 / Published 7 May 2014)

Abstract

RF magnetic probes can be used to measure not only the wavevector, but also the polarization of waves in plasmas. A 5-channel RF magnetic probe (5ch-RFMP) was installed in the TST-2 spherical tokamak and the waves were studied in detail during lower hybrid wave injection experiments. From the polarization measurements, the poloidal RF magnetic field is found to be dominant. In addition to polarization, components of k perpendicular to the major radial direction were obtained from phase differences among the five channels. The radial wavenumber was obtained by scanning the radial position of the 5ch-RFMP on a shot by shot basis. The measured wavevector and polarization in the plasma edge region were consistent with those calculated from the wave equation for the slow wave branch. While the waves with small and large k∥ were excited by the antenna, only the small k∥ component was measured by the 5ch-RFMP; this suggests that the waves with larger k∥ were absorbed by the plasma.

Keywords

RF magnetic probe, lower hybrid wave, spherical tokamak, wavevector, polarization

DOI: 10.1585/pfr.9.3402040

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References

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This paper may be cited as follows:

Takahiro SHINYA, Akira EJIRI, Yuichi TAKASE, Takuma WAKATSUKI, Takuya OOSAKO, Naoto TSUJII, Hidetoshi KAKUDA, Hirokazu FURUI, Junichi HIRATSUKA, Takuma INADA, Kazuhiro IMAMURA, Keishun NAKAMURA, Ayaka NAKANISHI, Masateru SONEHARA, Hiro TOGASHI, Shintaro TSUDA, Takashi YAMAGUCHI, Hiroshi KASAHARA, Kenji SAITO, Tetsuo SEKI, Fujio SHIMPO, Yoshihiko NAGASHIMA, Osamu WATANABE and Takuma YAMADA, Plasma Fusion Res. 9, 3402040 (2014).