  Nonlinear edge localized modes in a tokamak are examined using global
three-dimensional resistive magnetohydrodynamics simulations. Coherent
current-carrying filament (ribbon-like) structures wrapped around the torus are
nonlinearly formed due to nonaxisymmetric reconnecting current sheet
instabilities, the so called peeling-like edge localized modes. These fast
growing modes saturate by breaking axisymmetric current layers isolated near
the plasma edge and go through repetitive relaxation cycles by expelling
current radially outward and relaxing it back. The local bi-directional
fluctuation-induced electromotive force (emf) from the edge localized modes,
the dynamo action, relaxes the axisymmetric current density and forms current
holes near the edge.
