Electrostatic full-f gyrokinetic simulation of microturbulence in tokamak using canonical Maxwellian distribution
Haotian Chen, Pengfei Liu, Xishuo Wei, Zhihong LinElectrostatic full-f global gyrokinetic simulations using a canonical Maxwellian distribution find that ion temperature gradient turbulence in a tokamak exhibits a transition after which the transport level decreases until the system reaches a steady state. The transport coefficient exhibits Bohm-like scaling before the transition and gyro-Bohm scaling after the transition, with a reduction of the transport level due to the interaction between drift wave turbulence and zonal flows. This transition is associated with the long-time evolution of the distribution function toward a nonlinear steady state consistent with the turbulence. In the steady-state turbulence, the E × B staircases form and exhibit quasi-regular long-lived meso-scale structures that regularize the turbulence.