Study of ion turbulent transport and profile formations using global gyrokinetic full-f Vlasov simulation

Abstract

A global gyrokinetic toroidal full- f five-dimensional Vlasov simulation GT5D (Idomura et al 2008 Comput. Phys. Commun. 179 391)is extended including sources and collisions. Long time tokamak micro-turbulence simulations in open system tokamak plasmas are enabled for the first time based on a full- f gyrokinetic approach with self-consistent evolutions of turbulent transport and equilibrium profiles. The neoclassical physics is implemented using the linear Fokker–Planck collision operator, and the equilibrium radial electric field E r is determined self-consistently by evolving equilibrium profiles. In ion temperature gradient driven turbulence simulations in a normal shear tokamak with on-axis heating, key features of ion turbulent transport are clarified. It is found that stiff ion temperature T i profiles are sustained with globally constant L ti ≡ | T i / T i ′| near a critical value, and a significant part of the heat flux is carried by avalanches with 1/ f type spectra, which suggest a self-organized criticality. The E r shear strongly affects the directions of avalanche propagation and the momentum flux. Non-diffusive momentum transport due to the E r shear stress is observed and a non-zero (intrinsic) toroidal rotation is formed without momentum input near the axis.