Full- gyrokinetic simulations of ohmic L-mode plasmas in linear and saturated ohmic confinement regimes

Idomura, Yasuhiro; Dif-Pradalier, G.*; Garbet, X.*; Sarazin, Y.*; Tore Supra Teams*

Physics of Plasmas, 30(4), p.042508_1 - 042508_18, 2023/04

https://doi.org/10.1063/5.0127346

Two time slices in linear and saturated ohmic confinement (LOC and SOC) regimes in a Tore Supra ohmic L-mode discharge are analyzed using nonlinear global full- gyrokinetic simulations, and qualitative features of the LOC-SOC transition are reproduced. The exhaust of carbon impurity ions is caused by fast ion mixing, which is driven by the toroidal field stress. The intrinsic rotation develops in the opposite direction between the LOC and SOC phases, which is characterized by the different features of the mode asymmetry between trapped electron modes in the LOC phase and ion temperature gradient driven modes in the SOC phase, leading to the change of the profile shear stress. The energy fluxes of electrons and deuterium ions are dominant in the LOC and SOC phases, respectively, and the ratio of the energy confinement time between two phases agree with the experimental value.