TY - JOUR
T1 - Extension of Operation Region for Steady State Operation on QUEST by Integrated Control with Hot Walls
AU - Hasegawa, Makoto
AU - Hanada, Kazuaki
AU - Yoshida, Naoaki
AU - Idei, Hiroshi
AU - Ido, Takeshi
AU - Nagashima, Yoshihiko
AU - Ikezoe, Ryuya
AU - Onchi, Takumi
AU - Kuroda, Kengoh
AU - Kawasaki, Shoji
AU - Higashijima, Aki
AU - Nagata, Takahiro
AU - Shimabukuro, Shun
AU - Nakamura, Kazuo
N1 - Funding Information:
This work was supported by a Grant-in-Aid for JSPS Fellows (KAKENHI Grant Number 16H02441, 24656559) and the NIFS Collaboration Research Program (NIFS19KUTR136). This work was also supported in part by the Collaborative Research Program of the Research Institute for Applied Mechanics, Kyushu University.
Publisher Copyright:
© 2021 The Japan Society of Plasma Science and Nuclear Fusion Research
PY - 2021
Y1 - 2021
N2 - The controllability of particle supply during long-term discharge in a high-temperature environment was investigated at the Q-shu University Experiment with steady state spherical tokamak (QUEST). QUEST has a high-temperature wall capable of active heating and cooling as a plasma-facing wall. With this hot wall, a temperature rise test was conducted with 673 K as the target temperature. It was confirmed that the hot wall could maintain the temperature above 600 K. Feedback control of particle fueling was conducted to control Hα emission, which is closely related to influx to the wall. Using this particle fueling control and setting the hot wall temperature to 473 K, it was possible to obtain a discharge of more than 6 h. In this discharge, the fueling rate of particles decreased with time, and finally became zero, losing the particle fueling controllability. However, as soon as the cooling water started to flow through the hot wall, particles could be supplied again, and controllability was restored. Thus, indicating that temperature control of the plasma first wall is important even in the hightemperature environment of 473 K to control particle retention of the wall.
AB - The controllability of particle supply during long-term discharge in a high-temperature environment was investigated at the Q-shu University Experiment with steady state spherical tokamak (QUEST). QUEST has a high-temperature wall capable of active heating and cooling as a plasma-facing wall. With this hot wall, a temperature rise test was conducted with 673 K as the target temperature. It was confirmed that the hot wall could maintain the temperature above 600 K. Feedback control of particle fueling was conducted to control Hα emission, which is closely related to influx to the wall. Using this particle fueling control and setting the hot wall temperature to 473 K, it was possible to obtain a discharge of more than 6 h. In this discharge, the fueling rate of particles decreased with time, and finally became zero, losing the particle fueling controllability. However, as soon as the cooling water started to flow through the hot wall, particles could be supplied again, and controllability was restored. Thus, indicating that temperature control of the plasma first wall is important even in the hightemperature environment of 473 K to control particle retention of the wall.
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U2 - 10.1585/pfr.16.2402034
DO - 10.1585/pfr.16.2402034
M3 - Article
AN - SCOPUS:85112637159
SN - 1880-6821
VL - 16
SP - 1
EP - 8
JO - Plasma and Fusion Research
JF - Plasma and Fusion Research
ER -