Plasma and Fusion Research

Volume 13, 3402051 (2018)

Regular Articles

Radial Profile Measurements of Electron Temperature and Density Using the Thomson Scattering System in GAMMA 10/PDX

Masayuki YOSHIKAWA, Junko KOHAGURA, Masayuki CHIKATSU, Yoriko SHIMA, Mizuki SAKAMOTO, Yousuke NAKASHIMA, Ryutaro MINAMI, Ichihiro YAMADA¹⁾, Ryo YASUHARA¹⁾, Hisamichi FUNABA¹⁾, Takashi MINAMI²⁾ and Naoki KENMOCHI³⁾

: Plasma Research Center, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8577, Japan
1): National Institute for Fusion Science, 322-6 Oroshi-cho, Toki, Gifu 509-5292, Japan
2): Institute of Advanced Energy, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan
3): Graduate School of Frontier Sciences, University of Tokyo, Kashiwa, Chiba 277-8561, Japan

(Received 21 December 2017 / Accepted 28 March 2018 / Published 10 May 2018)

Abstract

We developed the YAG Thomson scattering (TS) system for electron temperature and density radial profiles in a single laser shot in the tandem mirror GAMMA 10/PDX. The optical collection system for the TS light is constructed using spherical mirrors and nine bundled optical fibers. The measurable radial positions are 5-cm intervals in a region of ± 20 cm due to the fixed position of the bundled optical fibers, which are set on a fixed-height optical platform. We replaced this with a lab jack to make the bundled optical fiber positions movable. Consequently, we can measure the radial profiles of the electron temperature in more detail. Moreover, we added a third spherical light collection mirror at the bottom of the main spherical collection mirror to increase the TS light intensity in the edge plasma region. In this way, we can obtain a slightly larger TS signal intensity than in the case without a third collection mirror. The radial electron temperatures and densities at 15 radial positions in GAMMA 10/PDX are successfully obtained. For the in-situ calibration of the electron density measurements of the TS system, we compare the TS system measurements to the electron line density measured using a microwave interferometer system.

Keywords

Thomson scattering, radial profile, electron temperature, electron density, tandem mirror GAMMA 10/PDX

DOI: 10.1585/pfr.13.3402051

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