Transition from neoclassical to turbulent electron diffusion

Electron diffusion in tokamak geometry is calculated including both the Coulomb collisional pitch angle scattering and the electromagnetic drift wave fluctuation spectrum. In the weak fluctuation limit the neoclassical banana‐plateau diffusion coefficient is recovered. At higher fluctuation levels typical of the mixing length amplitude the anomalous transport formulas of drift wave turbulence are recovered using test particle simulations.