Observation of multi-scale turbulence and non-local transport in LHD plasmas.

Authors :: Tokuzawa, T.
Inagaki, S.
Ida, K.
Itoh, K.
Ido, T.
Shimizu, A.
Takahashi, H.
Kitajima, S.
Tamura, N.
Yoshinuma, M.
Tsuchiya, H.
Yamada, I.
Tanaka, K.
Akiyama, T.
Nagayama, Y.
Kawahata, K.
Watanabe, K. Y.
Yamada, H.
Source :: Physics of Plasmas; May2014, Vol. 21 Issue 5, p055904-1-055904-6, 6p
Publication Year :: 2014
Abstract: We have studied two types of spatio-temporal turbulence dynamics in plasmas in the Large Helical Device, based on turbulence measurements with high spatial and temporal resolution. Applying conditional ensemble-averaging to a plasma with Edge-Localized Modes (ELMs), fast radial inward propagation of a micro-scale turbulence front is observed just after ELM event, and the propagation speed is evaluated as ~100 m/s. A self-organized radial electric field structure is observed in an electrode biasing experiment, and it is found to realize a multi-valued state. The curvature of the radial electric field is found to play an important role for turbulence reduction. [ABSTRACT FROM AUTHOR]