Multi-Scale Drift Turbulence Dynamics in Ohmic Discharge as Measured at the FT-2 Tokamak and Modeled by Full-f Gyrokinetic ELMFIRE-code

Quantitative reproduction of selected micro, meso, and macro-scale transport phenomena as measured in the FT-2 tokamak is reached by Elmfire global full f nonlinear gyrokinetic particle-in-cell simulation predictions. A detailed agreement with mean equilibrium flows, oscillating fine-scale zonal flows and turbulence spectra observed by a set of sophisticated microwave back-scattering techniques as well as a good fit of the thermal diffusivity data are demonstrated. Both the shift and the broadening of the power spectrum of synthetic and experimental Doppler reflectometry diagnostics have been found to overlap perfectly at various radial positions, indicating similar rotation and spreading of the selected density fluctuations. At the same time similar radial electric field dynamics and outward GAM propagation have been observed by comparisons of the probability distribution function, the coherence, the standard deviation and the dominant frequency of the simulated and experimentally measured radial electric field fluctuations, identifying the turbulent driven GAM as a key contributor to the observed burstiness of the radial electric field affected by impurity ions.