Plasma and Fusion Research

Volume 18, 1405012 (2023)

Regular Articles

Development of Thomson Scattering Measurement System for Long Duration Discharges on the QUEST Spherical Tokamak
Kaori KONO, Takeshi IDO, Akira EJIRI1), Kazuaki HANADA, Qilin YUE, Makoto HASEGAWA, Yi PENG1), Seiya SAKAI, Ryuya IKEZOE, Hiroshi IDEI, Syoji KAWASAKI, Kengoh KURODA, Takumi ONCHI, Yoshihiko NAGASHIMA and Seowon JANG1)
Kyushu University, Kasuga 816-8580, Japan
1)
The University of Tokyo, Kashiwa 277-8561, Japan
(Received 13 December 2022 / Accepted 18 January 2023 / Published 24 February 2023)

Abstract

The Thomson scattering control system has been modified to measure the time evolution of the electron density and temperature profiles during long duration discharges in the QUEST spherical tokamak. The system consists of a signal generator and a control circuit. The former accepts a QUEST main trigger and provides multiple triggers, each of which starts a short-term (e.g. 15 s) measurement. The latter provides triggers to synchronize the oscilloscope and laser oscillation during a short-term measurement. The system was used in 1000 s long duration discharges in QUEST, and the temporal evolutions of density and temperature profiles were obtained successfully. It was found the profiles are stationary after about 300 s.

Keywords

long duration discharge, Thomson scattering, spherical tokamak, hot wall, steady state plasma, QUEST

DOI: 10.1585/pfr.18.1405012

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