Gyrokinetic simulations of core turbulence and thermal transport in the high-beta(P) discharge on EAST

The properties of core turbulence and thermal transport are investigated for EAST high-beta(P) (beta(P) similar to 3.1) plasmas with dominant electron heating (T-e/T-i> 1) via gyrokinetic simulation with the NLT code. Linear simulations identify that the electrostatic eta(e)-driven trapped electron mode (eta(e)-TEM) dominates in the core region (rho< 0.7) and the ion temperature gradient (ITG) mode dominates in the out region (rho >= 0.7), consistent with the linear threshold analysis of micro-instabilities. Sensitivity analysis shows that the normalized electron density gradient (R/L-ne) and ITG (R/L-Ti) are two effective parameters to stabilize TEM instability. Nonlinear simulations are also carried out and compared with the experimental results, which show that the electron thermal internal transport barrier (ITB) in EAST high-beta(P)plasma is determined by the TEM-induced turbulence. A higher zonal flow shearing rate is observed in the ITB region (0.2 更多