Gyrokinetic Simulation of Turbulence in the High-βN Discharge on the Experimental Advanced Superconducting Tokamak.

Experiments on Experimental Advanced Superconducting Tokamak (EAST) were performed with high normalized beta () and favorable energy confinement () for the operating space achieved in EAST. Gyrokinetic simulations were carried out for four different cases with the experimental plasma parameters and tokamak equilibrium data. It was found that the favorable confinement is effectively maintained when increases to 1.9. The radial distribution of potential fluctuation during turbulence saturation phase is consistent with that of thermal transport diffusivity. Turbulence with higher toroidal modes becomes important as increases, and zonal flow shearing rate suppresses the turbulence when increases to 1.9, which is responsible for the well-maintained confinement. [ABSTRACT FROM AUTHOR]