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(EXP5/01) Dynamic Behaviour of Transport in Normal and Reversed Shear Plasmas with Internal Barriers in JT-60U

S. V. Neudatchin¹⁾, T. Takizuka²⁾, Yu. Dnestrovskij¹⁾, H. Shirai²⁾, T. Fujita²⁾, A. Isayama²⁾, Y. Kamada²⁾, Y. Koide^2)
 
1) Nuclear Fusion Institute, RRC ``Kurchatov Institute'', Moscow, Russia
²⁾ Japan Atomic Energy Research Institute, Naka Fusion Research Establishment, Naka-machi, Naka-gun, Ibaraki-ken 311-0193, Japan

Abstract.  Transport evolution in reverse shear (RS) and normal shear (NrS) JT-60U tokamak plasmas with internal transport barrier (ITB) is described as a combination of various fast and slow time scales processes. Abrupt in time and wide in space ($\sim$0.3 of minor radius) variations of electron and ion heat diffusivities $\delta$$\chi$e, i (seen as ``spontaneous-like'' simultaneous rise and decay of Te,i in two spatial zones) are found for weak ITBs in both RS and NrS plasmas. Profiles of $\delta$$\chi$e, i in RS plasmas with strong ITB are usually localized near ITB ``foot'' inside smaller space region. The maximum of the heat flux variation is located near position of the minimum of safety factor q in various RS plasmas, and variation is extended in positive shear region. Inward and outward heat pulse propagations created by $\delta$$\chi$e, i and sawtooth-like crashes are analyzed, small values of $\chi$e, i and absence of heat pinch are found in ITB region. Another source of abrupt $\delta$$\chi$e, i inside most of plasma volume, including significant part of weak ITB in RS plasmas, is seen as ELM-induced H-L transitions.

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