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Title: Mean flows and blob velocities in scrape-off layer (SOLT) simulations of an L-mode discharge on Alcator C-Mod

Two-dimensional scrape-off layer turbulence (SOLT) code simulations are compared with an L-mode discharge on the Alcator C-Mod tokamak [M. Greenwald, et al., Phys. Plasmas 21, 110501 (2014)]. Density and temperature profiles for the simulations were obtained by smoothly fitting Thomson scattering and mirror Langmuir probe (MLP) data from the shot. Simulations differing in turbulence intensity were obtained by varying a dissipation parameter. Mean flow profiles and density fluctuation amplitudes are consistent with those measured by MLP in the experiment and with a Fourier space diagnostic designed to measure poloidal phase velocity. Blob velocities in the simulations were determined from the correlation function for density fluctuations, as in the analysis of gas-puff-imaging (GPI) blobs in the experiment. In the simulations, it was found that larger blobs moved poloidally with the ExB flow velocity, vE , in the near-SOL, while smaller fluctuations moved with the group velocity of the dominant linear (interchange) mode, vE + 1/2 vdi, where vdi is the ion diamagnetic drift velocity. Comparisons are made with the measured GPI correlation velocity for the discharge. The saturation mechanisms operative in the simulation of the discharge are also discussed. In conclusion, it is found that neither sheared flow nor pressure gradientmore » modification can be excluded as saturation mechanisms.« less
Authors:
 [1] ;  [1] ;  [1] ;  [2] ;  [2] ;  [2] ;  [3]
  1. Lodestar Research Corp., Boulder, CO (United States)
  2. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
  3. Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
Publication Date:
OSTI Identifier:
1256738
Grant/Contract Number:
FG02-97ER54392
Type:
Accepted Manuscript
Journal Name:
Physics of Plasmas
Additional Journal Information:
Journal Volume: 23; Journal Issue: 6; Related Information: (Provide citations for supplementary items published with journal articles, or any other citation directly supporting the document you are submitting. Or, see the Related DOIs field below.); Journal ID: ISSN 1070-664X
Publisher:
American Institute of Physics (AIP)
Research Org:
Lodestar Research Corp., Boulder, CO (United States)
Sponsoring Org:
USDOE Office of Science (SC), Fusion Energy Sciences (FES) (SC-24)
Contributing Orgs:
Enter names of organizations that provided significant assistance but not direct funding
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY velocity measurement; tokamaks; shear flows; turbulence simulations; plasma flows