The problem of anomalous transport due to drift wave turbulence (in a simpleslab geometry) in the limit of strong turbulence is treated using a recentlydeveloped approach which introduces a new type of approximation (the decorrelation trajectorymethod). A hybrid kinetic equation isderived for the average distribution function (the density profile):it appears to be a typical non-Markovian equation. In the limit ofweak turbulence, this equation can be Markovianized, and the known results ofquasilinear transport theory are recovered. In the opposite limit of verystrong turbulence the memory effects become quite important. As a result, thetransport process is governed by a truly non-Markovian diffusion equation ofthe type appearing in the theory of continuous time random walks(CTRW). The shape and the evolution in time of the density profile are thenprofoundly altered, as compared to the usual solution of the normal diffusionequation.
Velocity diffusion in plasma waves excited by electron beams