FRACTAL DIAGRAMS OF MAGNETIC-FIELD LINES

The hamiltonian character of the perturbed magnetic held lines of a co nfined plasma let them be described by an area-preserving map. We use the fractal diagrams to analyse the destruction of the magnetic field lines of a Reversed Field configuration, when its magnetic configurati on is described by a Generalized Standard Map. The fractal diagrams sh ow that the dynamics of the magnetic surfaces is very dependent on the kind of magnetic perturbation, mainly on the number of modes of the p erturbative spectrum.