Plasma and Fusion Research

Volume 15, 1401035 (2020)

Regular Articles

Two-Dimensional Hα Emission Measurements Using the Multi-Channel Hα Array System in GAMMA 10/PDX
Tomoya YAMASAKI, Masayuki YOSHIKAWA, Junko KOHAGURA, Yoriko SHIMA, Hiroyuki NAKANISHI, Shun SUTO, Tomoya MOURI, Mizuki SAKAMOTO and Yousuke NAKASHIMA
Plasma Research Center, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8577, Japan
(Received 15 April 2019 / Accepted 7 April 2020 / Published 8 June 2020)

Abstract

We developed a multi-channel Hα array system to measure two-dimensional (2D) radial profiles of Hα emissivity in the central cell of the tandem mirror GAMMA 10/PDX. It consists of a 2D optical collection system, which contains twelve channels of lenses, Hα filters, and bundled optical fibers in vertical and horizontal directions. To study Hα emission behavior and its fluctuation in the hot-ion mode plasma experiments with additional plasma heating application, we used the modified Phillips-Tikhonov tomography method. After applying the fast Fourier transform analysis to the 2D Hα emissivity profiles, we could successfully obtain the 2D fluctuation images for the first time. These results are useful for the detailed study of fluctuations in magnetically confined plasma.

Keywords

Hα measurement, Phillips-Tikhonov method, tomography, tandem mirror GAMMA 10/PDX

DOI: 10.1585/pfr.15.1401035

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