The influence of filament positions on the arc discharge characteristics of a negative hydrogen ion source for a neutral beam injector were studied by simulations and experiments. We have made a simulation code named PRIMELOC2,” which calculates the orbits of primary electrons emitted from cathode filaments, including collisions with H2 gas molecules filled in the source, to obtain the spatial distribution of ionization points. We applied this code to a large negative hydrogen ion source having an external magnetic filter for LHD-NBI No. 1 (neutral beam injector 1 for a large helical device). As a result of the calculations, we have found that the moving area of emitted primary electrons differs markedly according to the filament positions. Calculation results agreed well with the experimental results of high-power arc discharge and the spatial distribution of plasma parameters obtained by Langmuir probe measurements. By applying PRIMELOC2 to filament–arc ion sources, we can choose appropriate areas in arc chambers for filament positioning.

1.
K.
Watanabe
et al.,
7th International Symposium on the Production and Neutralization of Negative Ions and Beams, Brookhaven National Laboratory, 1995
,
AIP Conf. Proc.
No. 380 (
AIP
,
New York
,
1996
).
2.
R. S. Hemsworth, H. D. Feist, T. Inoue, E. Kussel, D. Murdoch, A. Panasenkov, K. Shibata, M. Tanii, and M. Watson, Proceedings of the 16th Symposium on Fusion Engineering, Vol. 1 (1995), p. 264.
3.
O. Kaneko, Y. Oka, M. Osakabe, Y. Takeiri, K. Tsumori, R. Akiyama, E. Asano, T. Kuroda, and A. Ando, Proceedings of the 16th Symposium on Fusion Engineering, Vol. 2 (1995), p. 1082.
4.
K.
Tsumori
,
T.
Takanashi
,
S.
Asano
,
M.
Osakabe
,
Y.
Takeiri
,
Y.
Oka
,
E.
Asano
,
T.
Kawamoto
,
R.
Akiyama
,
T.
Okuyama
,
Y.
Suzuki
, and
O.
Kaneko
,
8th International Symposium on the Production and Neutralization of Negative Ions and Beams, Villagium de Giens, 1997
,
AIP Conf. Proc.
No. 439 (
AIP
,
New York
,
1998
).
5.
Y.
Takeiri
,
M.
Osakabe
,
K.
Tsumori
,
Y.
Oka
,
O.
Kaneko
,
E.
Asano
,
T.
Kawamoto
, and
R.
Akiyama
,
Rev. Sci. Instrum.
69
,
977
(
1998
).
6.
Y.
Takeiri
,
T.
Takanashi
,
O.
Kaneko
,
Y.
Oka
,
A.
Ando
,
K.
Tsumori
, and
T.
Kuroda
,
Fusion Eng. Des.
26
,
501
(
1995
).
7.
T.
Takanashi
,
Y.
Takeiri
,
O.
Kaneko
,
Y.
Oka
,
K.
Tsumori
, and
T.
Kuroda
,
Rev. Sci. Instrum.
67
,
1024
(
1996
).
8.
K.
Hashimoto
and
S.
Asano
,
Fusion Eng. Des.
26
,
495
(
1995
).
9.
K.
Hashimoto
,
J. Plasma Fusion Res.
72
,
145
(
1996
) (in Japanese).
10.
S.
Tanaka
,
M.
Akiba
,
H.
Horiike
,
M.
Matsuoka
,
Y.
Ohara
, and
Y.
Okumura
,
Rev. Sci. Instrum.
57
,
145
(
1986
).
11.
O.
Kaneko
,
Y.
Oka
,
K.
Sakurai
, and
T.
Kuroda
,
Rev. Sci. Instrum.
57
,
67
(
1986
).
12.
Y.
Ohara
,
M.
Akiba
,
H.
Horiike
,
H.
Inami
,
Y.
Okumura
, and
S.
Tanaka
,
J. Appl. Phys.
61
,
1323
(
1987
).
13.
K.
Watanabe
,
M.
Araki
,
M.
Dairaku
,
H.
Horiike
,
Y.
Ohara
,
Y.
Okumura
,
S.
Tanaka
, and
K.
Yokoyama
,
Rev. Sci. Instrum.
61
,
1694
(
1990
).
14.
K.
Watanabe
,
M.
Araki
,
M.
Dairaku
,
H.
Horiike
,
Y.
Ohara
,
Y.
Okumura
,
J.
Pamela
,
S.
Tanaka
, and
K.
Yokoyama
,
Rev. Sci. Instrum.
62
,
2142
(
1991
).
15.
S.
Ido
,
H.
Hasebe
, and
Y.
Fujita
,
Jpn. J. Appl. Phys., Part 1
32
,
4761
(
1993
).
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