Edge transport issues remain one of the main unknowns for future machines and in particular ITER. The understanding of the physical mechanisms explaining particles and heat fluxes in the outer part of the plasma are fundamental for the determination and the optimization of performances and plasma facing components life expectancy. A lot of effort has been made in the last decade towards the development of consistent models and codes based on first principal balance equations. The results of this effort demonstrated that, although small scale turbulence largely dominates transport in the edge plasma, large scales structures are also key players in the particle and heat exhaust. They not only generate machine scale flows which are likely to explain heat load, impurity deposition and detachment threshold asymmetries, but also they interact non-linearly with the turbulence changing locally the properties of transport. A proper description of this complex interplay is necessary to understand current observations and extrapolate to future devices.



This PhD proposal aims at studying the generation of large scale structures in the edge plasma of tokamaks and their interplay with the (mostly turbulent) transport. Particular focus will be given to electric field structures. The work will involve developing analytical or semi-analytical models which will then be validated using available transport and turbulence numerical codes. The development of specific numerical codes may also be expected. Results will then be compared with experimental results from the Tore Supra tokamak or from collaboration with other machines, either existing or obtained from dedicated new experiments.