Anomalous transport and complexity in plasma turbulence

A new and more physical approach is investigated to study the nonlinear evo lution of threshold instabilities, where the physical quantities are no lon ger separated into their average and fluctuating parts. This is the case wh ere fluxes are fixed and profiles are allowed to fluctuate. These systems e xhibit intermittent ballistic bursts for radial transport. Radially propaga ting fronts develop over a broad range of time and spatial scales. We revie w transport results obtained using this approach on 2D and 3D edge tokamak turbulence models. A low dimensional transport model is proposed and allows us to show the competition between diffusive and ballistic transport in th is convective type turbulence.