Comparison of Scrape-off Layer Turbulence in Alcator C-Mod with Three Dimensional Gyrofluid Computations

Zweben, S. J. ; Scott, B. D. ; Terry, J. L. ; LaBombard, B. ; Hughes, J. W. ; Stotler, D. P.

关键词: FLUCTUATIONS;    GEOMETRY;    PLASMA DENSITY;    SOLS;    SPECTRA;    TURBULENCE Scrape-off Layer (SOL);    Turbulence;    Tokamaks;   

DOI  :  10.2172/963546
RP-ID  :  PPPL-4438
PID  :  OSTI ID: 963546
Others  :  TRN: US0903631

学科分类：原子、分子光学和等离子物理

美国|英语

来源: SciTech Connect

【 摘 要 】

This paper describes quantitative comparisons between turbulence measured in the scrape-off layer (SOL) of Alcator C-Mod [S. Scott, A. Bader, M. Bakhtiari et al., Nucl. Fusion 47, S598 (2007)] and three dimensional computations using electromagnetic gyrofluid equations in a two-dimensional tokamak geometry. These comparisons were made for the outer midplane SOL for a set of inner-wall limited, near-circular Ohmic plasmas. The B field and plasma density were varied to assess gyroradius and collisionality scaling. The poloidal and radial correlation lengths in the experiment and computation agreed to within a factor of 2 and did not vary significantly with either B or density. The radial and poloidal propagation speeds and the frequency spectra and poloidal k-spectra also agreed fairly well. However, the autocorrelation times and relative Da fluctuation levels were higher in the experiment by more than a factor of 2. Possible causes for these disagreements are discussed. 2009 American Institute of Physics.