量研学術機関リポジトリ「QST-Repository」は、国立研究開発法人 量子科学技術研究開発機構に所属する職員等が生み出した学術成果（学会誌発表論文、学会発表、研究開発報告書、特許等）を集積しインターネット上で広く公開するサービスです。 Welcome to QST-Repository where we accumulates and discloses the academic research results(Journal Publications, Conference presentation, Research and Development Report, Patent, etc.) of the members of National Institutes for Quantum Science and Technology.
Thank you very much for using our website. On the 11th of March 2019, this site was moved from our own network server to the JAIRO Cloud network server. If you previously bookmarked this site, that bookmark will no longer work. We would be grateful if you could bookmark the website again. Thank you very much for your understanding and cooperation.
Spatio-temporal structures of ion heat flux and radial electric field are investigated on JT-60U to understand a mechanism of the internal transport barrier (ITB) formation. Contrary to the conventional argument that the ITB formation is due to the E × B flow shear suppressions on turbulence, we observe that the E × B shearing rate during the ITB formation is not enough for turbulence suppressions with kρi ∼ 1. Another finding is that the ITB is formed simultaneously with abrupt decreases of ion heat flux in the global region (like the report in Neudatchine et al 1999 Plasma Phys. Control. Fusion 41 L39), and the gradient–flux relations are non-diffusively developed step by step. These observations suggest the importance of the change in the long-radial fluctuations, which is previously observed in JT-60U (Nazikian et al 2005 Phys. Rev. Lett. 94 135002). Therefore, the model of effects by non-uniformity of the radial electric field, under the condition where the scale separation is violated, is employed to explain such fluctuation quenching. Consistent results are obtained showing that the non-uniformity of the radial electric field effectively works on the fluctuations with long-radial wavelength and increases the temperature gradient. It seems natural that the suppression of the long-radial fluctuations drives the global transport improvement to form the ITB.
Spatio-temporal evolutions of ion heat flux and radial electric field during internal transport barrier formation on JT-60U
