Self-consistent saturation of plasma profile and kinetic ballooning modes in the global, total-f gyrokinetic code XGC

Kinetic ballooning modes (KBMs) could be one of the ultimate limiters of the plasma energy content and its gradient. We demonstrate saturation of the plasma profile in self-organization with the KBM turbulence, the neoclassical physics, and the sheared E×B flow in a model tokamak plasma using a global total-f gyrokinetic code XGC. XGC uses mixed-variable and pull-back transformation methods together with the total-f algorithm [1,2] and nonlinear Fokker-Planck collision operator. The E×B shear regulates the turbulence level during the short transit time scale dynamics (<0.01 ms) and the profile relaxations are responsible for the turbulence level in the longer time scale (>0.1 ms). Radial heat-flux due to the self-organized plasma profile and KBM turbulence is in power-balance with the plasma heating.