3D simulations of turbulent mixing in a simplified slab-divertor geometry

Walkden, N.R.; Riva, Fabio Matteo; Dudson, B.D.; Ham, C.; Militello, F.; Moulton, D.; Nicholas, T.; Omotani, J.T.

doi:10.1016/j.nme.2018.12.005

Back

Journal article

3D simulations of turbulent mixing in a simplified slab-divertor geometry

Walkden, N.R. CCFE-UKAEA, Culham Science Centre, Oxfordshire, United Kingdom
Riva, Fabio Matteo ORCID Istituto ricerche solari Aldo e Cele Daccò (IRSOL), Faculty of Informatics, Università della Svizzera italiana Switzerland - CCFE-UKAEA, Culham Science Centre, Oxfordshire, United Kingdom
Dudson, B.D. York Plasma Institute, University of York, United Kingdom
Ham, C. CCFE-UKAEA, Culham Science Centre, Oxfordshire, United Kingdom
Militello, F. CCFE-UKAEA, Culham Science Centre, Oxfordshire, United Kingdom
Moulton, D. CCFE-UKAEA, Culham Science Centre, Oxfordshire, United Kingdom
Nicholas, T. CCFE-UKAEA, Culham Science Centre, Oxfordshire, United Kingdom - York Plasma Institute, University of York, United Kingdom
Omotani, J.T. CCFE-UKAEA, Culham Science Centre, Oxfordshire, United Kingdom

2019

Published in:

Nuclear Materials and Energy. - 2019, vol. 18, p. 111-117

English 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.

Collections