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Oct 13 – 18, 2014
Hotel Park Inn Pribaltiyskaya
Europe/Moscow timezone

Development of Divertor Simulation Research in the GAMMA 10/PDX Tandem Mirror

Oct 17, 2014, 2:00 PM
4h 45m
Green 8-9 (Hotel Park Inn Pribaltiyskaya)

Green 8-9

Hotel Park Inn Pribaltiyskaya

Saint Petersburg, Russian Federation
Poster Poster 8

Speaker

Prof. Yousuke Nakashima (Plasma Research Center, University of Tsukuba)

Description

This paper presents the first achievement of detachment from high temperature plasma equivalent to the SOL plasma of tokamaks using a large tandem mirror device. In Plasma Research Center, University of Tsukuba, we have started divertor simulation experiments at the end-cell of GAMMA 10/PDX (E-divertor) in order to realize the divertor simulation closely resemble to actual divertor environment [1, 2]. The first experiment for realizing detached plasma state from the high-temperature plasmas has been performed using H_2 and noble gas injection in the divertor simulation experimental module (D-module) recently installed in the west end-cell of GAMMA 10/PDX. Here, the plasma with n_e ~2×10^18 m^-3 and T_i// ~150 eV was produced with two ICRF waves (RF1 and RF2) in the upstream region (central-cell). The highest electron density of 2.4×10^18 m^-3 was obtained by simultaneous injection of H_2 and Xe into D-module. The particle and heat fluxes on the V-shaped target plate mounted in D-module were measured and the dependence on the Ar plenum pressure was examined. As increasing the amount of injection gas, both particle and heat fluxes continuously decrease. It is also observed that the electron temperature is drastically reduced from few tens eV to ~3 eV due to the Ar injection. Furthermore, in the case with H_2 and Xe, the ion flux was almost fully suppressed at the V-shaped corner. At the same time, 2-D image of Hα emission captured with the fast camera showed the clear detachment of emission zone from the target plate. Above results clearly show the evidence of plasma detachment in D-module. Recently two antennas for additional ICRF heating (RF3) were installed in anchor cells in order to build up both particle and heat fluxes at the end-cell. A remarkable increase of the plasma density and end-loss ion flux is achieved during RF3. We evaluated the particle flux at the mirror exit by investigating correlation between particle flux determined from the probe measurements near the mirror throat and the end-loss ion current measured with end-loss ion energy analyzer (ELIEA). From this evaluation, the particle flux is estimated to be 1.7×10^23/m^2 s at the end-mirror exit. [1] Y. Nakashima, et al., Fusion Eng. Design volume 85 issue 6 (2010) 956-962. [2] Y. Nakashima, et al., Journal of Nuclear Materials 438 (2013) S738-S741.
Paper Number FIP/P8-10
Country or International Organisation Japan

Primary author

Prof. Yousuke Nakashima (Plasma Research Center, University of Tsukuba)

Co-authors

Prof. Akio Sagara (National Institute for Fusion Science) Prof. Akira Tonegawa (Tokai University) Prof. Akiyoshi Hatayama (Keio University) Dr Hirotaka Kubo (Japan Atomic Energy Agency) Dr Hiroto Matsuura (Osaka Prefecture University) Mr Hisato Takeda (Plasma Research Center, University of Tsukuba) Prof. Isao Katanuma (University of Tsukuba) Dr Junko Kohagura (Plasma Research Center, University of Tsukuba) Mr Katsuhiro Hosoi (Plasma Research Center, University of Tsukuba) Mr Kazuya Ichimura (Plasma Research Center, University of Tsukuba) Dr Kensuke Oki (Plasma Research Center, University of Tsukuba) Dr Mafumi Hirata (Plasma Research Center, University of Tsukuba) 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) Ms Miki Iwamoto (Plasma Research Center, University of Tsukuba) Prof. Mizuki Sakamoto (Plasma Research Center, University of Tsukuba) Dr Nobuhiro Nishino (Hiroshima University) Mr Nobuyuki Asakura (Japan Atomic Energy Agency) Prof. Noriyasu Ohno (Nagoya Univeristy) Dr Ryutaro MINAMI (Plasma Research Center, University of Tsukuba) Dr Ryuya Ikezoe (Plasma Research Center, University of Tsukuba) Dr Shiniciro Kado (Kyoto University) Dr Shinji Nagata (Tohoku University) Dr Suguru Masuzaki (National Institute for Fusion Science) Prof. Tatsuo Shikama (Tohoku University) Dr Tomoharu Numakura (Plasma Research Center, University of Tsukuba) Prof. Tsuyoshi Imai (Plasma Research Center, University of Tsukuba) Dr Tsuyoshi Kariya (Plasma Research Center, University of Tsukuba) Mr Yasunari Hosoda (Plasma Research Center, University of Tsukuba) Prof. Yoshihiko Hirooka (National Institute for Fusion Science) Prof. Yoshio Ueda (Osaka University)

Presentation materials