[en] In the tokamak Tore Supra, the magnetic field ensuring the confinement is stochastic at the plasma edge due to a resonant perturbation. This perturbation is created by a set of six helicoidal coils inside the vacuum vessel, the ergodic divertor. The first part of the study concerns the analysis of the transport of particles and energy in a fusion plasma in presence of a stochastic magnetic field, without physical wall. The effective transport of electrons, i.e. heat transport, increases. The ions transport increases too but less than heat transport. The discrepancy produces a mean radial electric field. The second part is devoted to the influence of the physical wall. The topology of the magnetic connexion on the wall is precisely determined with the code Mastoc. The transport of particles and energy is then described from the confined plasma until the wall. This study enlights severals important observations of the experience Tore Supra in the ergodic divertor configuration: the spreading of the power deposition on the wall components without anomalous concentration, the robustness of this configuration relatively to misalignment, the edge structures visible in H_αlight during plasma reattachment. In order to study the transport of impurity ions, a variational approach of minimum entropy production has been developped. This principle is applied to the calculation of the neoclassical diffusion of impurity ions with the radial electric field. This electric field deconfines ions if the pressure profile is not balanced by a Lorentz force, i.e. if the plasma is locked in rotation, poloidally and toroidally, because of magnetic perturbation or friction force