Investigation of self-organized critically behavior of edge plasma transport in Torus experiment of technology oriented research

Xu, H. Y.; Weynants, R. R.; Samm, U.; Huber, A.; Unterberg, B.; Jachmich, S.

doi:10.1063/1.1810160

Journal Article

Investigation of self-organized critically behavior of edge plasma transport in Torus experiment of technology oriented research

Xu, H. Y. ; Jachmich, S. ; Weynants, R. R. ; Huber, A.FZJ* ; Unterberg, B.FZJ* ; Samm, U.FZJ*

2004
American Institute of Physics [S.l.]

Physics of plasmas 11, 5413 - 5422 (2004) [10.1063/1.1810160]

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Please use a persistent id in citations: http://hdl.handle.net/2128/1842 doi:10.1063/1.1810160

Abstract: The self-organized criticality (SOC) behavior of the edge plasma transport has been studied using fluctuation data measured in the plasma edge and the scrape-off layer of Torus experiment of technology oriented research tokamak [H. Soltwisch , Plasma Phys. Controlled Fusion 26, 23 (1984)] before and during the edge biasing experiments. In the "nonshear" discharge phase before biasing, the fluctuation data clearly show some of the characteristics associated with SOC, including similar frequency spectra to those obtained in "sandpile" transport and other SOC systems, slowly decaying long tails in the autocorrelation function, values of Hurst parameters larger than 0.5 at all the detected radial locations, and a radial propagation of avalanchelike events in the edge plasma area. During the edge biasing phase, with the generation of an edge radial electric field E-r and thus of E(r)xB flow shear, contrary to theoretical expectation, the Hurst parameters are substantially enhanced in the negative flow shear region and in the scrape-off layer as well. Concomitantly, it is found that the local turbulence is well decorrelated by the E(r)xB velocity shear, consistent with theoretical predictions. (C) 2004 American Institute of Physics.

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