Self-consistent dynamics of impurities in magnetically confined plasmas: turbulence intermittency and non-diffusive transport

Journal Article · Sun Jan 01 00:00:00 EST 2012 · Physical Review Letters

DOI:https://doi.org/10.1103/PhysRevLett.109.185005· OSTI ID:1057492

Futatani, S. ^[1]; Del-Castillo-Negrete, Diego B ^[2]; Garbet, X ^[3]; Benkadda, S. ^[4]; Dubuit, N. ^[5]

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1. ITER Organization, Saint Paul Lez Durance, France
2. ORNL
3. CEA Cadarache, St. Paul lex Durance, France
4. CEA, IRFM, France
5. International Institute for Fusion Science-Universite de Provence

Self-consistent turbulent transport of high concentration impurities in magnetically confined fusion plasmas is studied using a three-dimensional nonlinear fluid global turbulence model which includes ion temperature gradient (ITG) and trapped electron mode (TEM) instabilities. It is shown that the impurity concentration can have a dramatic feedback in the turbulence and, as a result, it can significantly change the transport properties of the plasma. High concentration impurities can trigger strong intermittency, that manifests in non-Gaussian heavy tails of the pdfs of E B and the ion-temperature flux fluctuations. At the heart of this self-consistent coupling is the existence of inward propagating ion temperature fronts with a sharp gradient at the leading edge that give rise to instabilities and avalanche-like bursty transport. Numerical evidence of time non-locality in the turbulent transport of high concentration impurities is also presented.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE Office of Science (SC)
• DOE Contract Number: DE-AC05-00OR22725
• OSTI ID: 1057492
• Journal Information: Physical Review Letters, Vol. 109, Issue 18; ISSN 0031--9007
• Country of Publication: United States
• Language: English