High power and long-pulse negative ion extractor, which is composed of the plasma grid (PG) and the extraction grid (EXG), is newly developed toward the neutral beam injector for heating and current drive of future fusion machines such as ITER, JT-60 Super Advanced and DEMO reactor. The PG is designed to enhance surface production of negative ions efficiently by applying the chamfered aperture. The efficiency of the negative ion production for the discharge power increased by a factor of 1.3 against that of the conventional PG. The EXG is also designed with the thermal analysis to upgrade the cooling capability for the long pulse operation of >1000 s required in ITER. Though the magnetic field for electron suppression is reduced to 0.75 of that in the conventional EXG due to this upgrade, it was experimentally confirmed that the extracted electron current can be suppressed to the allowable level for the long pulse operation. These results show that newly developed extractor has the high potential for the long pulse extraction of the negative ions.
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February 2014
14th International Conference on Ion Sources (ICIS 2011)
12-16 September 2011
Giardini-Naxos, Sicily (Italy)
Research Article|
January 16 2014
Development of negative ion extractor in the high-power and long-pulse negative ion source for fusion applicationa)
M. Kashiwagi;
M. Kashiwagi
b)
Japan Atomic Energy Agency (JAEA)
, 801-1 Mukoyama, Naka 311-0193, Japan
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N. Umeda;
N. Umeda
Japan Atomic Energy Agency (JAEA)
, 801-1 Mukoyama, Naka 311-0193, Japan
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H. Tobari;
H. Tobari
Japan Atomic Energy Agency (JAEA)
, 801-1 Mukoyama, Naka 311-0193, Japan
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A. Kojima;
A. Kojima
Japan Atomic Energy Agency (JAEA)
, 801-1 Mukoyama, Naka 311-0193, Japan
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M. Yoshida;
M. Yoshida
Japan Atomic Energy Agency (JAEA)
, 801-1 Mukoyama, Naka 311-0193, Japan
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M. Taniguchi;
M. Taniguchi
Japan Atomic Energy Agency (JAEA)
, 801-1 Mukoyama, Naka 311-0193, Japan
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M. Dairaku;
M. Dairaku
Japan Atomic Energy Agency (JAEA)
, 801-1 Mukoyama, Naka 311-0193, Japan
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T. Maejima;
T. Maejima
Japan Atomic Energy Agency (JAEA)
, 801-1 Mukoyama, Naka 311-0193, Japan
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H. Yamanaka;
H. Yamanaka
Japan Atomic Energy Agency (JAEA)
, 801-1 Mukoyama, Naka 311-0193, Japan
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K. Watanabe;
K. Watanabe
Japan Atomic Energy Agency (JAEA)
, 801-1 Mukoyama, Naka 311-0193, Japan
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T. Inoue;
T. Inoue
Japan Atomic Energy Agency (JAEA)
, 801-1 Mukoyama, Naka 311-0193, Japan
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M. Hanada
M. Hanada
Japan Atomic Energy Agency (JAEA)
, 801-1 Mukoyama, Naka 311-0193, Japan
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b)
Author to whom correspondence should be addressed. Electronic mail: kashiwagi.mieko@jaea.go.jp
a)
Contributed paper, published as part of the Proceedings of the 15th International Conference on Ion Sources, Chiba, Japan, September 2013.
Rev. Sci. Instrum. 85, 02B320 (2014)
Article history
Received:
September 09 2013
Accepted:
November 04 2013
Citation
M. Kashiwagi, N. Umeda, H. Tobari, A. Kojima, M. Yoshida, M. Taniguchi, M. Dairaku, T. Maejima, H. Yamanaka, K. Watanabe, T. Inoue, M. Hanada; Development of negative ion extractor in the high-power and long-pulse negative ion source for fusion application. Rev. Sci. Instrum. 1 February 2014; 85 (2): 02B320. https://doi.org/10.1063/1.4852297
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