Impact of collisionality on fluctuation characteristics of micro-turbulence
- Ecole Polytechnique, LPP, CNRS UMR 7648, 91128 Palaiseau (France)
- CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France)
The influence of changing collisionality on density fluctuation characteristics is studied during dedicated {nu}* scaling experiments, using Doppler backscattering system. First, the repartition of fluctuation energy over different spatial scales, as represented by the wavenumber spectrum, is investigated and a modification of the shape of the perpendicular wavenumber spectrum in the low wavenumber part of the spectrum is observed when changing collisionality. In addition, a new procedure to evaluate the dispersion relation of micro-turbulence is presented. From the behavior of the perpendicular mean velocity of density fluctuations with the perpendicular wavenumber, different dispersion relations are obtained between low and high collisionality cases.
- OSTI ID:
- 21532169
- Journal Information:
- Physics of Plasmas, Vol. 18, Issue 1; Other Information: DOI: 10.1063/1.3536648; (c) 2011 American Institute of Physics; ISSN 1070-664X
- Country of Publication:
- United States
- Language:
- English
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