Abstract
The microscopic structure of drift-wave turbulence perpendicular to the magnetic field is investigated in a toroidal plasma by means of multi-probe arrays. The dependence of structure sizes on the drift-scale ρs is studied with the objective of classifying the range of perpendicular wavenumbers k⊥ ρs with respect to the analytical linear drift-wave dispersion relation. Wavenumbers in the range 0.2-1.5 are found according to a scaling around . Values k⊥ ρs < 0.3, for which a dispersion-free dynamics is expected, are found in H and D. Biasing experiments on discharges in this range show that very strong E × B flow shear changes the characteristic mode structure in favour of coherent large-scale structures, which can be related to local turbulent inward transport as a result of modifications in the phase relation between density and potential fluctuations.
Original language | English |
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Article number | 024007 |
Journal | Plasma Sources Science and Technology |
Volume | 17 |
Issue number | 2 |
DOIs | |
State | Published - 1 May 2008 |
Externally published | Yes |