(EX9/1) Study of Energetic Ion Transport in the Large Helical Device
M. Sasao1), S. Murakami1),
M. Isobe1), A. V. Krasilnikov2),
S. Iiduka3), K. Itoh1), N. Nakajima1),
M. Osakabe1), K. Saito4), T. Seki1),
Y. Takeiri1), T. Watari1), H. Yamada1),
N. Ashikawa5), P. de Vries1),
M. Emoto1), H. Funaba1), M. Goto1),
K. Ida1), H. Idei1), K. Ikeda1),
S. Inagaki1), N. Inoue1), S. Kado1),
O. Kaneko1), K. Kawahata1),
K. Khlopenkov1), T. Kobuchi5),
A. Komori1), S. Kubo1), R. Kumazawa1),
S. Masuzaki1), T. Minami1),
J. Miyazawa1), T. Morisaki1),
S. Morita1), S. Muto1), T. Mutoh1),
Y. Nagayama1), Y. Nakamura1),
H. Nakanishi1), K. Narihara1),
K. Nishimura1), N. Noda1), T. Notake4, )
Y. Liang5), S. Ohdachi1), N. Ohyabu1),
Y. Oka1), T. Ozaki1), B. J. Peterson1),
R. O. Pavlichenko1), A. Sagara1),
S. Sakakibara1), R. Sakamoto1),
H. Sasao5), K. Sato1), M. Sato1),
T. Shimozuma1), M. Shoji1), H. Suzuki1),
M. Takechi1), N. Tamura5), K. Tanaka1),
K. Toi1), T. Tokuzawa1), Y. Torii4),
K. Tsumori1), , I. Yamada1),
S. Yamaguchi1), S. Yamamoto4),
M. Yokoyama1), Y. Yoshimura1),
K. Y. Watanabe1), O. Motojima1), and
M. Fujiwara1)
1) National Institute for Fusion Science, Toki,
509-5292, Japan
2) Troitsk Institute for Innovating and Fusion Research, Troitsk,
Russia
3) Department of Nuclear Engineering, Nagoya University, 464-8603,
Japan
4) Department of Energy Engineering and Science, Nagoya University,
464-8603, Japan
5) Department of Fusion Science, School of Mathematical and Physical
Science, Graduate University for Advanced Studies, Hayama, 240-0193, Japan
Abstract. The confinement property of high energy ions and the role of
ripple induced transport have been studied in the Large Helical Device
(LHD). Tangential beam particles are injected at 90 - 150 kV by
negative-ion-based neutral beam injectors, and perpendicular high energy
particles are generated by Ion Cyclotron Range of Frequency (ICRF) heating.
Energy distributions of high energy ions have been measured by fast neutral
particle analyzers based on natural diamond detectors, specially developed
for this experiment. Time evolution of perpendicular tail temperature in
decaying phase after the ICRF termination indicates that the fast particles
deeply trapped in helical ripples are well confined longer than the
collisional relaxation time, when
ne > 1019m- 3 in the
inward shifted configuration (
Rax = 3.6m). In lower density
plasma, however, faster decay than the classical prediction is observed.
The tangential energy spectra in a low density steady state plasma of the
standard configuration (
Rax = 3.75m) also show the deviation
from 2D Fokker-Plank simulation. The global 5-D transport simulation code
including the ripple induced transport shows good agreement with measured
spectra, and this suggests an important role of ripple induced transport in
the standard configuration of LHD.
IAEA 2001
