skip to main content

SciTech ConnectSciTech Connect

Title: Synergistic cross-scale coupling of turbulence in a tokamak plasma

For the first time, nonlinear gyrokinetic simulations spanning both the ion and electron spatio-temporal scales have been performed with realistic electron mass ratio ((m{sub D}∕m{sub e}){sup 1∕2 }= 60.0), realistic geometry, and all experimental inputs, demonstrating the coexistence and synergy of ion (k{sub θ}ρ{sub s}∼O(1.0)) and electron-scale (k{sub θ}ρ{sub e}∼O(1.0)) turbulence in the core of a tokamak plasma. All multi-scale simulations utilized the GYRO code [J. Candy and R. E. Waltz, J. Comput. Phys. 186, 545 (2003)] to study the coupling of ion and electron-scale turbulence in the core (r/a = 0.6) of an Alcator C-Mod L-mode discharge shown previously to exhibit an under-prediction of the electron heat flux when using simulations only including ion-scale turbulence. Electron-scale turbulence is found to play a dominant role in setting the electron heat flux level and radially elongated (k{sub r} ≪ k{sub θ}) “streamers” are found to coexist with ion-scale eddies in experimental plasma conditions. Inclusion of electron-scale turbulence in these simulations is found to increase both ion and electron heat flux levels by enhancing the transport at the ion-scale while also driving electron heat flux at sub-ρ{sub i} scales. The combined increases in the low and high-k driven electron heat flux may explain previously observed discrepanciesmore » between simulated and experimental electron heat fluxes and indicates a complex interaction of short and long wavelength turbulence.« less
Authors:
 [1] ;  [2] ; ;  [3] ;  [4]
  1. Oak Ridge Institute for Science and Education (ORISE), Oak Ridge, Tennessee 37831 (United States)
  2. University of California - San Diego, La Jolla, California 92093 (United States)
  3. MIT - Plasma Science and Fusion Center, Cambridge, Massachusetts 02139 (United States)
  4. General Atomics, P.O. Box 85608, San Diego, California 92186 (United States)
Publication Date:
OSTI Identifier:
22403271
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 21; Journal Issue: 11; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; COUPLING; ELECTRONS; HEAT FLUX; INTERACTIONS; IONS; L-MODE PLASMA CONFINEMENT; PLASMA; SIMULATION; TURBULENCE