Tokamak plasma magnetic islands formation and evolution

Plasma motion in a tokamak is studied by means of numerical solution of two-dimensional MHD equations with finite conductivity. For helical mode m=2 production and evolution of magnetic islands has been studied. It is shown that with a sufficiently sharp distribution of current in plasma, the islands cannot pass to the center of the filament but diffuse to its periphery. The passage of the islands on the filament surface leads to the plasma escape on the diaphragm and chamber walls