Abstract
Beam emission spectroscopy (BES) measurements of ion-scale density fluctuations in the MAST tokamak are used to show that the turbulence correlation time, the drift time associated with ion temperature or density gradients, the particle (ion) streaming time along the magnetic field, and the magnetic drift time are consistently comparable, suggesting a "critically balanced" turbulence determined by the local equilibrium. The resulting scalings of the poloidal and radial correlation lengths are derived and tested. The nonlinear time inferred from the density fluctuations is longer than the other times; its ratio to the correlation time scales as ν*i-0. 8±0.1, where ν*i=ion  ⠀Šcollision   rate/streaming   rate. This is consistent with turbulent decorrelation being controlled by a zonal component, invisible to the BES, with an amplitude exceeding those of the drift waves by ∼ν*i-0.8. Published by the American Physical Society.
| Original language | English |
|---|---|
| Article number | 145002 |
| Journal | Physical Review Letters |
| Volume | 110 |
| Issue number | 14 |
| DOIs | |
| Publication status | Published - ápr. 1 2013 |
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ASJC Scopus subject areas
- Physics and Astronomy(all)
Cite this
Experimental signatures of critically balanced turbulence in MAST. / Ghim, Y. C.; Schekochihin, A.; Field, A. R.; Abel, I. G.; Barnes, M.; Colyer, G.; Cowley, S. C.; Parra, F. I.; Dunai, D.; Zoletnik, S.
In: Physical Review Letters, Vol. 110, No. 14, 145002, 01.04.2013.Research output: Article
}
TY - JOUR
T1 - Experimental signatures of critically balanced turbulence in MAST
AU - Ghim, Y. C.
AU - Schekochihin, A.
AU - Field, A. R.
AU - Abel, I. G.
AU - Barnes, M.
AU - Colyer, G.
AU - Cowley, S. C.
AU - Parra, F. I.
AU - Dunai, D.
AU - Zoletnik, S.
PY - 2013/4/1
Y1 - 2013/4/1
N2 - Beam emission spectroscopy (BES) measurements of ion-scale density fluctuations in the MAST tokamak are used to show that the turbulence correlation time, the drift time associated with ion temperature or density gradients, the particle (ion) streaming time along the magnetic field, and the magnetic drift time are consistently comparable, suggesting a "critically balanced" turbulence determined by the local equilibrium. The resulting scalings of the poloidal and radial correlation lengths are derived and tested. The nonlinear time inferred from the density fluctuations is longer than the other times; its ratio to the correlation time scales as ν*i-0. 8±0.1, where ν*i=ion  ⠀Šcollision   rate/streaming   rate. This is consistent with turbulent decorrelation being controlled by a zonal component, invisible to the BES, with an amplitude exceeding those of the drift waves by ∼ν*i-0.8. Published by the American Physical Society.
AB - Beam emission spectroscopy (BES) measurements of ion-scale density fluctuations in the MAST tokamak are used to show that the turbulence correlation time, the drift time associated with ion temperature or density gradients, the particle (ion) streaming time along the magnetic field, and the magnetic drift time are consistently comparable, suggesting a "critically balanced" turbulence determined by the local equilibrium. The resulting scalings of the poloidal and radial correlation lengths are derived and tested. The nonlinear time inferred from the density fluctuations is longer than the other times; its ratio to the correlation time scales as ν*i-0. 8±0.1, where ν*i=ion  ⠀Šcollision   rate/streaming   rate. This is consistent with turbulent decorrelation being controlled by a zonal component, invisible to the BES, with an amplitude exceeding those of the drift waves by ∼ν*i-0.8. Published by the American Physical Society.
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U2 - 10.1103/PhysRevLett.110.145002
DO - 10.1103/PhysRevLett.110.145002
M3 - Article
AN - SCOPUS:84875983254
VL - 110
JO - Physical Review Letters
JF - Physical Review Letters
SN - 0031-9007
IS - 14
M1 - 145002
ER -