Progress on anomalous transport in tokamaks, drift waves and nonlinear structures

Fluid and kinetic theory of drift wave turbulence and zonal flows are compared. The result from particle in cell codes that transport is reduced and zonal flows become stronger when the parallel nonlinearity is included is interpreted in terms of removing dissipative kinetic resonances from a fluid model. Also a kinetic derivation is given of the excitation of zonal flows and recent results on momentum transport are discussed. The recent results on particle pinches in fluid and kinetic codes are also interpreted in a similar way. General aspects of different fluid closures are discussed.