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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
Kusama, Yoshinori; Ishikawa, Masao; Takechi, Manabu; Nishitani, Takeo; Morioka, Atsuhiko; Sasao, Mamiko*; Isobe, Mitsutaka*; Krasilnikov, A.*; Kaschuck, Y.*
Proceedings of Plasma Science Symposium 2005/22nd Symposium on Plasma Processing (PSS-2005/SPP-22), p.395 - 396, 2005/00
The energetic neutral particles have been successfully measured with a natural diamond detector in the neutron and ray radiation circumstance of the JT-60U deuterium discharges. The diamond detector was covered with polyethylene and lead in order to reduce the neutron and ray background. The shield has shown expected shielding capability. A rapid increase in neutral particles has been observed at the onset of the Toroidal Alfven Eigenmode (TAE) excited by the negative-ion-based neutral beam injection. The energy range of increased neutral particles has agreed well with that predicted from the resonant interaction between the energetic ions and the TAE.
Ishikawa, Masao; Kusama, Yoshinori; Takechi, Manabu; Nishitani, Takeo; Morioka, Atsuhiko; Sasao, Mamiko*; Isobe, Mitsutaka*; Krasilnikov, A.*; Kaschuck, Y. A.*
Review of Scientific Instruments, 75(10), p.3643 - 3645, 2004/10
Times Cited Count:6 Percentile:35.7(Instruments & Instrumentation)Measurement of energy distribution of charge exchange neutral particles by using Natural Diamond Detector (NDD) has been started on the JT-60U Tokamak. Because the NDD is sensitive to neutrons and -rays too, the radiation shield has been set up around the NDD. Then energy distribution of neutral particles corresponding to injected neutral beam energy are successfully obtained. Also, enhance of neutral particle flux due to sawtooth oscillation and Alfven Eigenmode induced by N-NBI was observed. The performance of the NDD as CX neutral particle analyzer under the DD neutron filed was demonstrated on JT-60U.
Ishikawa, Masao; Shinohara, Koji; Takechi, Manabu; Matsunaga, Go; Kusama, Yoshinori; Krasilnikov, A.*; Kaschuck, Y.*; Isobe, Mitsutaka*; Nishitani, Takeo; Morioka, Atsuhiko; et al.
no journal, ,
Magnetohydrodynamics (MHD) instabilities with a frequency sweeping and then saturation of frequency as qmin decrease have been observed during Negative-ion-based Neutral Beam (NNB) injection in JT-60U Weak Shear (WS) plasmas. The frequency evolution of those MHD instabilities can be explained by Reversed-Shear-induced Alfvn Eigenemode model or Alfvn Cascade model. In recent experiments, a confinement degradation of energetic ions by such instabilities was clearly observed. In this work, we evoluate the confinement degradation of energetic ions by the instabilities usigng measurement of total neuron flux and neutron emission profile. Further, we will compare the confinement degradation by the above instabilities with that by Abrupt Large-amplitude Events (ALEs), which are bursting modes.