Plasma and Fusion Research

Volume 18, 2402025 (2023)

Regular Articles

Design Study of a Line Integrated Thomson Scattering System for TST-2 Spherical Tokamak Device
Akira EJIRI, Yu-Ting LIN, Seowon JANG, Yi PENG, Kouji SHINOHARA, Takeshi IDO1), Kaori KONO1) and Yoshihiko NAGASHIMA1)
The University of Tokyo, Kashiwa 277-8561, Japan
1)
Kyushu University, Kasuga 816-8580, Japan
(Received 16 December 2022 / Accepted 6 March 2023 / Published 27 April 2023)

Abstract

A design study of a line integrated Thomson scattering (TS) system with a complete backscattering configuration has been performed to clarify practical problems. Installation on the TST-2 spherical tokamak was assumed, and an optical system design with ready-made components, are adopted. Some practical aspects, such as aberration, masking effect of the laser combining mirror, misalignment are investigated by ray tracing calculations. The performance of density profile reconstruction was also investigated. It was found that a tangential-multi-chord measurement configuration on the midplane shows a good effective localization, and error enhancement in the reconstruction is small. In addition, the efficiency of the system is about an order of magnitude larger than the present conventional TS system in TST-2. The attractiveness of the line integrated TS measurements was demonstrated.

Keywords

Thomson scattering measurement, line integrated measurement, backscattering, profile reconstruction

DOI: 10.1585/pfr.18.2402025

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