Effect of Nonlinear Electron Landau Damping in Collisionless Drift-Wave Turbulence

Collisionless drift-wave turbulence is studied with numerical simulations in a three-dimensional sheared slab geometry. Nonlinear electron Landau damping associated with parallel trapping is found to substantially reduce the anomalous particle transport for low magnetic shear ( $\hat{s}<1\mathrm{}$), whereas it plays a very weak role for higher shear ( $\hat{s}>1\mathrm{}$). This result has implications for the construction of transcollisional Landau-fluid models for passing electrons in the edge ( $r/a>\mathrm{}0.8\mathrm{}$) of a tokamak.