Open AccessEdge Turbulence Imaging in the Alcator C-Mod Tokamak
Author(s) -
S. J. Zweben,
D.P. Stotler,
J.L. Terry,
B. LaBombard,
M. Greenwald,
Matthew W. Muterspaugh,
C.S. Pitcher,
K. Hallatschek,
R. J. Maqueda,
B. N. Rogers,
J. L. Lowrance,
V. Mastrocola,
G. Renda
Publication year - 2001
Language(s) - English
Resource type - Reports
DOI - 10.2172/792843
Subject(s) - alcator c mod , tokamak , turbulence , physics , maxima , computational physics , atomic physics , plasma , nuclear physics , mechanics , art , performance art , art history
The 2-D radial vs. poloidal structure of edge turbulence in the Alcator C-Mod tokamak [I.H. Hutchinson, R. Boivin, P.T. Bonoli et al., Nuclear Fusion 41(2001) 1391] was measured using fast cameras and compared with 3-D numerical simulations of edge plasma turbulence. The main diagnostic is Gas Puff Imaging (GPI), in which the visible D(subscript alpha) emission from a localized D(subscript 2) gas puff is viewed along a local magnetic field line. The observed D(subscript alpha) fluctuations have a typical radial and poloidal scale of approximately 1 cm, and often have strong local maxima (''blobs'') in the scrape-off layer. The motion of this 2-D structure motion has also been measured using an ultra-fast framing camera with 12 frames taken at 250,000 frames/sec. Numerical simulations produce turbulent structures with roughly similar spatial and temporal scales and transport levels as that observed in the experiment; however, some differences are also noted, perhaps requiring diagnostic improvement and/or additional physics in the numerical model