Unveiling stickiness regions of magnetic field lines in tokamaks

Stickiness refers to the destructed orbits in phase space that remain in a particular region around intact surfaces for a long time before entering the chaotic sea. In fusion plasmas, stickiness regions trap magnetic field lines for many toroidal turns and have considerable effect on plasma transport. We locate stickiness regions in the chaotic phase space of resonant magnetic perturbations in tokamak using three dynamical quantities which are field lines diffusion coefficient, maximal Lyapunov exponent and the growing rate of an infinitesimal line segment. We compare the values of these quantities in regular, stickiness and chaotic regions to find a criterion for distinguishing stickiness from chaotic and regular areas in phase space.