Speaker
Adam Dempsey
Description
See the full Abstract at http://ocs.ciemat.es/EPS2018ABS/pdf/P5.1026.pdf
Gyrofluid Simulations of Tokamak Edge Plasmas
A. Dempsey1 , H. Leggate1 , M. M. Turner1
1 Dublin City University, Dublin 9, Ireland
Filaments are field aligned structures that are known to form in the scrape-off-layer (SOL) in
tokamaks. These structures are composed of hot electrons and ions. They can constitute a non-
negligible thermal and particle flux on the first wall. As such the propagation of these structures
to the first wall is problematic. All unnecessary heat loading of structural components must be
avoided to prolong the lifetime of a fusion device. In order to arrive at an optimal design for a
next-generation machine it is advantageous to predict wall fluxes so that thermal loading and
tritium retention can be modelled. One approach to predicting such fluxes in plasmas is to rely
on simulation. However depending on which kinetic equation, closure and approximations are
used some physics can be lost. For instance, finite Larmor radius effects are often lost.
The approach described herein is to use a gyrofluid model. Gyrofluid models incorporate
higher order finite Larmor radius effects more naturally that other fluid models. The gyrofluid
model used in this study is briefly introduced [1] and initial progress towards solving it using
BOUT++ [2] is presented. The focus of this simulation is on filament dynamics as modified by
finite Larmor radius (FLR) effects. Of particular interest are filament-background interactions
and filament propagation near the SOL.
Figure 1: Filament density plots exhibiting typical radial propagation.
References
[1] Bruce Scott and Juri Smirnov, “Energetic consistency and momentum conservation in the gyrokinetic descrip-
tion of tokamak plasmas”, Physics of Plasmas, vol. 17, no. 11, aug 2010.
[2] B. D. Dudson, M. V. Umansky, X. Q. Xu, P. B. Snyder, and H. R. Wilson, “BOUT++: A framework for parallel
plasma fluid simulations”, Computer Physics Communications, vol. 180, no. 9, pp. 1467–1480, 2009.
This work has been carried out within the framework of the EUROfusion Consortium and has received funding
from the Euratom research and training programme 2014–2018 under grant agreement No 633053 The views and
opinions expressed herein do not necessarily reflect those of the European Commission.
