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(THP1/02) Self-Similarity and Structures of Plasma Turbulence

D. E. Newman1), B. A. Carreras2), V. E. Lynch2), D. Lopez-Bruna3)
 
1) Department of Physics, University of Alaska, Fairbanks, Alaska, U.S.A.
2) Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-8070, U.S.A
3) Asociación Euratom-CIEMAT, 28040 Madrid, Spain

Abstract.  Plasma edge fluctuations and induced fluxes measured in several types of confinement devices have been found to be self-similar over time scales between 10 times the turbulence decorrelation time and the plasma confinement time. These self-similarity parameters vary little from one device to another. In exploring the self-similarity properties, it has become clear that time and space measurements lead to different information on the structure of turbulence. Therefore, it is often not possible to clearly separate the poloidal and temporal structures of the turbulence with a single-point measure. This in turn implies that using the standard Taylor frozen flow hypothesis can be very misleading when applied to plasma turbulence. We have used simple 2 and 3-D turbulence models to investigate how 1) the multiple nonlinearities intrinsic to plasmas affect the self-similarity parameter for both temporal and poloidal structures and 2) how poloidal flows influence the single-point measurements. Understanding the temporal and spatial dynamics individually, as well as the relationships between the temporal and spatial dynamics for turbulent plasma systems is crucial to improving the comparison between model and experiment.

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IAEA 2001