1. 3D simulations of turbulent mixing in a simplified slab-divertor geometry
- Author
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Nick Walkden, Thomas Nicholas, F. Militello, John Omotani, Benjamin Daniel Dudson, Fabio Riva, David Moulton, and C. J. Ham
- Subjects
Nuclear and High Energy Physics ,Tokamak ,Materials Science (miscellaneous) ,Transport coefficient ,Rotational symmetry ,01 natural sciences ,010305 fluids & plasmas ,law.invention ,Physics::Plasma Physics ,law ,0103 physical sciences ,010302 applied physics ,Physics ,Turbulence ,Divertor ,Mechanics ,lcsh:TK9001-9401 ,Nuclear Energy and Engineering ,Heat flux ,Physics::Space Physics ,Slab ,lcsh:Nuclear engineering. Atomic power ,Electron temperature - Abstract
Three-dimensional simulations of plasma turbulence have been run using the STORM module of BOUT + + in a simple slab geometry aimed at representing a single, isolated tokamak divertor leg. Turbulence is driven primarily by the Kelvin-Helmholtz mechanism due to the sheared ExB flow that forms around the separatrix due to strong radial gradients in the sheath potential which arise from strong radial gradients in the electron temperature. The turbulence forms a mixing layer around the separatrix which spreads heat and particles into the private-flux region. The resulting spread of the electron heat flux is within the experimental range measured on MAST. An effective thermal transport coefficient which is approximately 10% of the Bohm value is measured from the simulations. When a transport coefficient of this magnitude is used in a diffusive axisymmetric simulation, the time-averaged radial profiles share similar features to the full turbulence simulation.
- Published
- 2019