Characteristics of turbulence-driven plasma flow and origin of experimental empirical scalings of intrinsic rotation
- Princeton University, Plasma Physics Laboratory, P. O. Box 451, Princeton, New Jersey 08543 (United States)
- University of California, San Diego, La Jolla, California 92093 (United States)
Toroidal plasma flow driven by turbulent torque associated with nonlinear residual stress generation is shown to recover the observed key features of intrinsic rotation in experiments. Specifically, the turbulence-driven intrinsic rotation scales close to linearly with plasma gradients and the inverse of the plasma current, qualitatively reproducing empirical scalings obtained from a large experimental data base. The effect of magnetic shear on the symmetry breaking in the parallel wavenumber spectrum is identified. The origin of the current scaling is found to be the enhanced k{sub ||} symmetry breaking induced by increased radial variation of the safety factor as the current decreases. The physics origin for the linear dependence of intrinsic rotation on the pressure gradient comes from the fact that both turbulence intensity and the zonal flow shear, which are two key ingredients for driving the residual stress, are increased with the strength of the turbulence drives, which are R/L{sub T{sub e}} and R/L{sub n{sub e}} for the collisionless trapped electron mode (CTEM). Highlighted results also include robust radial pinches in toroidal flow, heat and particle transport driven by CTEM turbulence, which emerge ''in phase,'' and are shown to play important roles in determining plasma profiles. Also discussed are the experimental tests proposed to validate findings from these gyrokinetic simulations.
- OSTI ID:
- 21537645
- Journal Information:
- Physics of Plasmas, Vol. 18, Issue 4; Other Information: DOI: 10.1063/1.3575162; (c) 2011 American Institute of Physics; ISSN 1070-664X
- Country of Publication:
- United States
- Language:
- English
Steady-state tokamak research: Core physics
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journal | December 2012 |
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