Abstract : In the Tore Supra tokamak , the magnetic field which ensures the confinement has been made stochastic at the plasma edge thanks to a resonant perturbation. This perturbation is produced by six helicoidal coils, the ergodic divertor, located inside the vacuum vessel. The first part of our study is the analysis of particles and energy transport in a plasma fusion in presence of a stochastic magnetic field, without solid wall. The effective transport of electrons, i.e. of heat, is greatly enhanced, and of ions also in a lower proportion. This difference produces an average radial electric field. In a second part, the influence of a solid wall is considered. Thanks to the MASTOC numerical code, the topology of the magnetic connexion to the wall is precisely determined. One could then describe the particle and energy transport from the core plasma to the plasma facing components. This study enlights some of the principal observations of the Tore Supra experiments in ergodic divertor configuration: the spreading of the power deposition on the different plasma facing components without anomalous concentration, the robutsness of this configuration against alignment default, the structures visible in H alpha light during plasma re-attachment. In order to study the impurity ion transport, a variationnal approach by minimum entropy prioduction has been developped. This variational principle has been applied to the calculation of the neoclassical diffusion of impurity ions in a electric average radial field. This average electric radial field deconfines ions if the pressure profil is not balanced by a Laplace force, i.e. if the plasma is locked in rotations, poloidal and toroidal, by a magnetic perturbation or a friction force.