CHARACTERIZATION OF THE ELECTRIC POTENTIAL ACROSS THE TOKAMAK

Abstract : The poloidally and toroidally symmetric mode of the electric potential is selfconsistently generated by turbulence. Its radial derivatives (the Zonal Flows and the electric shear) substantially affect confinement properties. We study the radial shape of the electric potential through statistical analysis on data from GYSELA, global gyrokinetic and flux-driven code. Two main features are retained in the simple projection on parabolic functions: the maximal depth and the slope (i.e. the electric field) at the edge. A preliminary trend is found in relation to the energy confinement: the well is deeper for increasing confinement.