Speaker
Dr
Naoyuki Fukumoto
(University of Hyogo)
Description
Compact toroid (CT) injection was conducted on several middle-class tokamaks in the previous experiments for development of an advance fueling method. We have carried out CT injection in a Spherical Tokamak (ST) plasma, for the first time, on QUEST equivalent to the tokamaks in facility size. The primary aim of the experiment is to produce a high-density ST plasma and control its density profile by CT fueling. The QUEST is designed for a ST confinement at the toroidal field B_T = 0.5 T for a pulse mode. The UH-CTI injector has a sufficient performance to penetrate into a ST plasma at B_T = 0.8 T. However the CT traveling distance from the injector nozzle to the separatrix on QUEST is 1.525 m, which is longer by about 1 m than that in the previous experiment on JFT-2M. It is also our objective to investigate the long CT transport with a drift tube. In the experiment, a CT plasma with a high density up to the order of 10^21 m^-3 at more than 200 km/s was injected perpendicularly on the magnetic axis on the midplane. Plasma responses to CT injection was obtained in an OH-ST plasma at V_form. = 17 kV and V_acc. = 25 kV for the CT formation and acceleration banks respectively. Plasma current had no adverse effect of CT injection. A line averaged electron density increased just after CT injection. Thus the long CT transport and the non-disruptive CT injection are successfully made. Electron density profile was also measured by Thomson scattering. The trigger system is set up to observe electron density profile at any given timing in the order of microseconds after CT injection. At the rather fast time of 0.5ms after CT injection, increment in electron density was observed on the peripheral channels. In this experimental research, we have successfully conducted CT injection in a ST plasma on QUEST. Non-disruptive CT fueling in an OH-ST plasma is obtained. Peripheral fuel particle deposition is observed by Thomson scattering.
This work was performed with the support and under the auspices of the NIFS Collaboration Research Program (NIFS14KUTR102, NIFS15KUTR112)
| Country or International Organization | Japan |
|---|---|
| Paper Number | PDP-16 |
Primary author
Dr
Naoyuki Fukumoto
(University of Hyogo)
Co-authors
Ms
Aki Higashijima
(Kyushu University)
Prof.
Akihide Fujisawa
(Kyushu University)
Dr
Akira Ejiri
(Graduate School of Frontier Sciences, The University of Tokyo)
Hideki Zushi
(Riam Kyushu University)
Mr
Hiro Togashi
(University of Tokyo)
Dr
Hiroshi Idei
(Research Institute for Applied Mechanics, Kyushu University)
Prof.
Kazuaki Hanada
(Advanced Fusion Research Center, Research Institute for Applied Mechanics, Kyushu University)
Prof.
Kazuo Nakamura
(Kyushu University)
Mr
Kazuya Toida
(University of Tokyo)
Mr
Kengo Awajitani
(University of Hyogo)
Dr
Kuzmin Aleksandrovich
(Kyushu University)
Dr
Makoto Hasegawa
(Kyushu University)
Prof.
Masayoshi Nagata
(University of Hyogo)
Prof.
Osamu Mitarai
(University of Saskatchewan)
Mr
Shoji Kawasaki
(Kyushu University)
Mr
Takahiro Nagata
(Kyushu University)
Dr
Takumi Onchi
(Kyushu University)
Dr
Yoshihiko Nagashima
(Kyushu University)
Prof.
Yuichi Takase
(University of Tokyo)
