Experimental signatures of critically balanced turbulence in MAST

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.

UR - https://www.scopus.com/pages/publications/84875983254

UR - https://www.scopus.com/pages/publications/84875983254#tab=citedBy

U2 - 10.1103/PhysRevLett.110.145002

DO - 10.1103/PhysRevLett.110.145002

M3 - Article

C2 - 25166998

SN - 0031-9007

VL - 110

JO - Physical review letters

JF - Physical review letters

IS - 14

M1 - 145002

ER -