THE RESISTIVE INTERCHANGE CONVECTION IN THE EDGE OF TOKAMAK PLASMAS

Theoretical results are presented addressing the behaviour of plasmas outside the separatrix i.e. in the region where the magnetic field lin es do not form closed magnetic surfaces. The resistive interchange mod el is used to describe self-consistently the generation of poloidal (o r toroidal) flow and the onset of ELMs, which appear as bubbles of inc reased density (or higher temperature). In addition, the decrease of t he turbulent transport processes as the velocity of the flow increases and its connection with the LH transition are discussed. The linear t heory of stability is applied and complemented by a full numerical sim ulation of the two-dimensional nonlinear equations. Analytic solutions for asymptotically small parameters in the nonlinear model are derive d and used for the explanation of the numerical results. Semi-phenomen ological turbulence balance equaitons for the resistive interchange co nvection are presented as well. Finally, these results are applied for the explanation of existing experiments.