Speaker
Prof.
Yousuke Nakashima
(Plasma Research Center, JpUTsukuba)
Description
This paper describes the characteristics of detached plasma produced by using hydrogen and noble gases together with the progress of high-heat and particle flux generation experiments in the GAMMA 10/PDX end-cell. In Plasma Research Center, University of Tsukuba, divertor simulation experiments have been started at the end-cell of GAMMA 10/PDX (E-divertor) [1]. In the GAMMA 10/PDX end-cell, plasma flow with high temperature (Ti = 100 ~ 400 eV, Te = 30 eV), heat and particle fluxes (> 10 MW/m^2, >10^23/m^2 s, respectively) have been produced under the high magnetic field (~1 Tesla), which cannot be attained by conventional liner devices [2]. We have succeeded in achieving detachment of high temperature plasma equivalent to the SOL plasma of tokamaks in spite of using a linear device with short connection length of magnetic field line. Various gases (N2, Ne, Ar, Xe) are examined to evaluate the effect of radiation cooling against the plasma flow of MW/m^2 level in a divertor simulation region and the following results are obtained: (i) Xe gas was most effective on electron cooling (down to ~2 eV) and reduction of heat and particle fluxes (1%, 3%, respectively). (ii) Ne gas was less effective. On the other hand, (iii) N2 gas showed more favorable effects than Ar. The above results are almost consistent with the observation from an absolutely calibrated visible spectrometer viewing the inside of D-module, such as (i) stronger emission from Xe I and II, (ii) significant molecular visible-emission from N2, etc. Furthermore, in the case with a simultaneous injection of Hydrogen and Xe gases, the ion flux was almost fully suppressed, which indicates the existence of Molecular Activated Recombination in D-module.
In plasma flow generation experiments, ICRF heating in anchor-cell successfully extended the particle flux up to 3.3 x 10^23/m^2 s in the end-cell. Superimposing the ECH pulse (380 kW x 5 ms) into the ICRF plasma also succeeded in extending the highest heat flux of ~15 MW/m^2 which exceeds the ITER divertor heat load in the steady state. These results will contribute to the progress in detached plasma operation and clarification of radiation cooling mechanism towards the development of the future divertor.
[1] Y. Nakashima, et al., Fusion Eng. Design volume 85 issue 6 (2010) 956-962.
[2] Y. Nakashima, et al., Journal of Nuclear Materials 463 (2015) 537-540.
| Country or International Organization | Japan |
|---|---|
| Paper Number | EX/P8-42 |
Primary author
Prof.
Yousuke Nakashima
(Plasma Research Center, JpUTsukuba)
Co-authors
Mr
Akihiro Terakado
(Plasma Research Center, JpUTsukuba)
Prof.
Akio Sagara
(National Institute for Fusion Science)
Prof.
Akira TONEGAWA
(Graduate School of Science, JpUTokai)
Prof.
Akiyoshi Hatayama
(Faculty of Science and Technology, JpUKeio)
Dr
Hirotaka KUBO
(Japan Atomic Energy Agency)
Dr
Hiroto MATSUURA
(Radiation Research Center, JpUOsaka Pref.)
Prof.
Isao Katanuma
(University of Tsukuba)
Dr
Junko KOHAGURA
(Plasma Research Center, JpUTsukuba)
Dr
Kazuya Ichimura
(Plasma Research Center, JpUTsukuba)
Prof.
Keiji SAWADA
(Graduate School of Science, JpUNagano)
Mr
Keita SHIMIZU
(Plasma Research Center, JpUTsukuba)
Mr
Kunpei Nojiri
(Plasma Research Center, JpUTsukuba)
Dr
Mafumi Hirata
(Plasma Research Center, JpUTsukuba)
Prof.
Makoto Ichimura
(Plasma Research Center, University of Tsukuba)
Dr
Mamoru Shoji
(National Institute for Fusion Science)
Dr
Masakatsu Fukumoto
(Japan Atomic Energy Agency)
Dr
Masayuki Yoshikawa
(University of Tsukuba)
Mr
Md. Maidul Islam
(Plasma Research Center, JpUTsukuba)
Mr
Md. Shahinul Islan
(Plasma Research Center, JpUTsukuba)
Prof.
Mizuki Sakamoto
(Plasma Research Center, JpUTsukuba)
Dr
Naomichi Ezumi
(Plasma Research Center, JpUTsukuba)
Dr
Nobuhiro NISHINO
(Graduate School of Engineering, JpUHiroshima)
Mr
Nobuyuki Asakura
(Japan Atomic Energy Agency)
Prof.
Noriyasu Ohno
(Graduate School of Engineering, Nagoya University)
Dr
Ryutaro MINAMI
(Plasma Research Center, University of Tsukuba)
Dr
Ryuya Ikezoe
(Plasma Research Center, University of Tsukuba)
Dr
Shinichiro KADO
(Institute of Atomic Energy, JpUKyoto)
Dr
Shinji NAGATA
(Institute for Material Research, JpUTohoku)
Prof.
Suguru MASUZAKI
(National Institute for Fusion Science)
Dr
Tomoharu NUMAKURA
(Plasma Research Center, JpUTsukuba)
Dr
Tomohide Nakano
(Japan Atomic Energy Agency)
Prof.
Tsuyoshi Imai
(Plasma Research Center, University of Tsukuba)
Dr
Tsuyoshi Kariya
(Plasma Research Center, University of Tsukuba)
Prof.
Yoshio Ueda
(Osaka University)
Prof.
Yoshishiko HIROOKA
(National Institute for Fusion Science)
