Global Gyrokinetic Particle Simulation of Turbulence and Transport
in Realistic Tokamak Geometry
W X Wang, Z Lin, W M Tang, W W Lee, S Ethier,
J L V Lewandowski, G Rewoldt, T S Hahm and J Manickam
A general geometry model has been developed for the gyrokinetic toroidal code
GTC with a number of highly desirable features including a systematic
treatment of plasma rotation and equilibrium E×B flow,
realistic plasma profiles and corresponding magnetohydrodynamic (MHD) equilibria.
A symmetry coordinate system is used to construct a relatively regular mesh in real
space for strongly shaped toroidal plasmas, which also facilitates straightforward visualization.
By rescaling the radial coordinate, grid size is correlated with the local gyroradius
which may vary substantially from the core to the edge.
Gyrokinetic transformation of potential and charge density between particle and
guiding center positions in general geometry is carefully treated,
taking into account the finite ratio of the poloidal to the total field
(B_{θ}/B).
The applied equilibrium E×B flow, which is believed to play
an important role in determining the turbulence level, is calculated from our
global neoclassical particle code GTCNeo.
In the large aspect ratio circular geometry limit, cross benchmarks
with the original GTC code show good agreement in real frequency, growth
rate, steadystate heat flux and zonal flow amplitude for the ion temperature gradient
driven microinstabilities (ITG modes).
