NONLINEAR ELECTROSTATIC TURBULENCE

A variational method expressing the self‐consistency of an electrostatic turbulence in a confined plasma is presented. It properly takes into account all types of resonances if the Kolmogorov broadening due the diffusion is small compared to the spectral width of the turbulent electric potential. The method is applied to study the possibility of a new type of drift turbulence in tokamaks where the various modes are strongly localized by nonlinear effects around their resonant surface. The passing electrons play a major role in driving such a turbulence, a result compatible with the observed increase of transport at the edge.