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Sasao, Mamiko*; Nishitani, Takeo; Krasilnikov, A.*; Popovichev, S.*; Kiptily, V.*; Kallne, J.*
Fusion Science and Technology, 53(2), p.604 - 639, 2008/02
Times Cited Count:31 Percentile:61.43(Nuclear Science & Technology)no abstracts in English
Donn, A. J. H.*; Costley, A. E.*; Barnsley, R.*; Bindslev, H.*; Boivin, R.*; Conway, G.*; Fisher, R.*; Giannella, R.*; Hartfuss, H.*; von Hellermann, M. G.*; et al.
Nuclear Fusion, 47(6), p.S337 - S384, 2007/06
Times Cited Count:335 Percentile:78.95(Physics, Fluids & Plasmas)no abstracts in English
Ishikawa, Masao; Nishitani, Takeo; Kusama, Yoshinori; Sukegawa, Atsuhiko; Takechi, Manabu; Shinohara, Koji; Krasilnikov, V. A.*; Kaschuck, Y.*; Sasao, Mamiko*; Isobe, Mitsutaka*; et al.
Plasma and Fusion Research (Internet), 2, p.019_1 - 019_11, 2007/05
no abstracts in English
Ishikawa, Masao; Takechi, Manabu; Shinohara, Koji; Matsunaga, Go; Kusama, Yoshinori; Fukuyama, Atsushi*; Krasilnikov, V. A.*; Kashuck, Yu.*; Nishitani, Takeo; Morioka, Atsuhiko; et al.
Proceedings of 21st IAEA Fusion Energy Conference (FEC 2006) (CD-ROM), 8 Pages, 2007/03
Confinement degradation of energetic ions due to Alfvn Eigenmodes (AEs) induced by negative-ion-based neutral beam injection for the classical confinement is quantitatively evaluated for the first time. AEs, whose frequency largely sweep with the time scale of a few hundreds millisecond as the minimum value of the safety factor decrease, have been observed in JT-60U. These mode behavior can be explained by reversed-shear induced AEs (RSAEs). Measured total neutron emission rate (Sn) in the presence of the AEs is compared with that predicted by a classical theory. As a result, confinement degradation of energetic ions is confirmed, Line-integrated neutron emission profile is also compared with that predicted when assuming that the confinement is classical. The result indicates energetic ions are transported from core region of the plasma due to these AEs. Further, changes in energy distribution of charge exchange neutral fluxes suggest radial transport is due to the resonance interaction between energetic ions and AEs.
Ishikawa, Masao; Takechi, Manabu; Shinohara, Koji; Kusama, Yoshinori; Matsunaga, Go; Krasilnikov, V. A.*; Kashuck, Y.*; Isobe, Mitsutaka*; Nishitani, Takeo; Sukegawa, Atsuhiko; et al.
Nuclear Fusion, 46(10), p.S898 - S903, 2006/10
Times Cited Count:16 Percentile:48.10(Physics, Fluids & Plasmas)Confinement degradation of energetic ions due to Alfvn eigenmodes (AEs) has been investigated with negative ion based neutral beam injection into JT-60U weak shear plasmas. AEs with a rapid frequency sweeping and then saturation as the minimum value of the safety factor decreases have been observed. This frequency behaviour can be explained by RSAE and the transition from RSAEs toTAEs. The associated change in the charge exchange neutral particle flux suggests energetic ion transport due to these AEs. The total neutron emission reduction rate in the presence of these AEs is evaluated by calculation using the orbit following Monte-Carlo code taking into account the change in bulk plasmas. The evaluation indicates confinement of energetic ions is degraded due to these AEs. In particular, it is found that the confinement degradation of energetic ions is maximum during the transition from RSAEs to TAEs.
Ishikawa, Masao; Takechi, Manabu; Shinohara, Koji; Kusama, Yoshinori; Cheng, C. Z.*; Matsunaga, Go; Todo, Yasushi*; Gorelenkov, N. N.*; Kramer, G. J.*; Nazikian, R. M.*; et al.
Nuclear Fusion, 45(12), p.1474 - 1480, 2005/12
Times Cited Count:38 Percentile:74.77(Physics, Fluids & Plasmas)To investigate energetic ion transport induced by Alfven eigenmodes (AEs) the neutron emission profile measurement and the charge exchange (CX) neutral particle flux measurement by Natural Diamond Detector has been performed simultaneously in the JT-60U for the first time. The energetic ion profiles inferred from these measurements indicate that ALEs cause a radial redistribution of energetic ions of limited energy range from the core region to the outer region of the plasma in weak shear plasmas. This energy range is consistent with the resonance condition between the mode and the energetic ions. In reversed shear plasmas, reversed-shear-induced AEs (RSAEs) and their transition to TAEs as the minimum value of the safety factor decreases has been observed. Neutron measurements suggest energetic ion loss is large in the transition phase from RSAEs to TAEs.
Ishikawa, Masao; Takechi, Manabu; Shinohara, Koji; Matsunaga, Go; Kusama, Yoshinori; Nishitani, Takeo; Sukegawa, Atsuhiko; Baba, Mamoru*; Itoga, Toshio*; Krasilnikov, V. A.*; et al.
no journal, ,
no abstracts in English