Simulation of ion-temperature-gradient turbulence in tokamaks
Results are presented from nonlinear gyrokinetic simulations of toroidal ion temperature gradient (ITG) turbulence and transport. The gyrokinetic simulations are found to yield values of the thermal diffusivity significantly lower than gyrofluid or IFS-PPPL-model predictions. A new phenomenon of nonlinear effective critical gradients larger than the linear instability threshold gradients is observed, and is associated with undamped flux-surface-averaged shear flows. The nonlinear gyrokineic codes have passed extensive validity tests which include comparison against independent linear calculations, a series of nonlinear convergence tests, and a comparison between two independent nonlinear gyrokinetic codes. Our most realistic simulations to date have actual reconstructed equilibria from experiments and a model for dilution by impurity and beam ions. These simulations highlight the need for still more physics to be included in the simulations
- Research Organization:
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC)
- DOE Contract Number:
- W-7405-Eng-48
- OSTI ID:
- 3934
- Report Number(s):
- UCRL-JC-130166; AT5020100; ON: DE00003934
- Resource Relation:
- Conference: 17th International Atomic Energy Agency Fusion Energy Conference, Yokohama, Japan, October 19-24, 1998
- Country of Publication:
- United States
- Language:
- English
Similar Records
Examination of stiff ion temperature gradient mode physics in simulations of DIII-D H-mode transport
Comparisons and physics basis of tokamak transport models and turbulence simulations