Spatiotemporal Structures of Edge Limit-Cycle Oscillation before L-to-H Transition in the JFT-2M Tokamak

T. Kobayashi, K. Itoh, T. Ido, K. Kamiya, S.-I. Itoh, Y. Miura, Y. Nagashima, A. Fujisawa, S. Inagaki, K. Ida, and K. Hoshino

Phys. Rev. Lett. 111, 035002 – Published 17 July 2013

Abstract

In this Letter, we report analyses of spatiotemporal dynamics of turbulence and structure in the limit-cycle oscillation (LCO) that precedes an L-to-H transition. Zonal flows are not observed during LCO, and the oscillation is the periodic generations or decays of barrier with edge-localized mean flow. Oscillatory Reynolds stress is found to be too small to accelerate the LCO flow, by considering the dielectric constant in magnetized toroidal plasmas. Propagation of changes of the density gradient and turbulence amplitude into the core is also observed.

Received 26 March 2013

DOI:https://doi.org/10.1103/PhysRevLett.111.035002

Authors & Affiliations

T. Kobayashi^1,*, K. Itoh^2,3, T. Ido², K. Kamiya⁴, S.-I. Itoh^3,5, Y. Miura⁴, Y. Nagashima^3,5, A. Fujisawa^3,5, S. Inagaki^3,5, K. Ida^2,3, and K. Hoshino⁴

¹Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, Kasuga 816-8580, Japan
²National Institute for Fusion Science, Toki 509-5292, Japan
³Itoh Research Center for Plasma Turbulence, Kyushu University, Kasuga 816-8580, Japan
⁴Japan Atomic Energy Agency, Naka 311-0193, Japan
⁵Research Institute for Applied Mechanics, Kyushu University, Kasuga 816-8580, Japan

^*Corresponding author. kobayashi@riam.kyushu-u.ac.jp

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Vol. 111, Iss. 3 — 19 July 2013

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