Instantaneous Correlation between ELM-like MHD Activity and Abrupt Non-local Reduction of Transport at Internal Transport Barrier Formation in JT-60U High-β_p Plasmas

摘要

Transport evolution in normal and reversed shear JT-60U tokamak plasmas with internal transport barrier (ITB) often occurs via non-local transport bifurcations. In the present paper, we highlight new type of edge-core instantaneous interplay in JT-60U high-β_p plasmas. Abrupt in time (ms timescale) and wide in space (～0.4 of minor radius) reduction of electron heat flux in the core (ITB-event) is correlated in ms timescale with the start of an ELM that creates enhanced level of H_α. This result gives a hint of the control to form the ITB immediately and non-locally by inducing the ELM-like MHD activity.