Topological properties of the edge ergodic layer in tokamak plasma

A topological property appearing in a tokamak with edge ergodized is a transition from a well-ordered system to a chaotic-fractal one. This transition often creates "nice" looking structures such as the well known Mandelbrot picture. In this paper, we present the visualization of the magnetic field structure observed in the torus experiment for technology oriented research-dynamic ergodic divertor, using an asymptotical mapping method. The effect of such a structure on the important transport issue in fusion devices is discussed