Plasma transport by turbulent homoclinic tangles in diverted tokamak plasmas*

Electromagnetic turbulence can generate a fluctuating homoclinic tangle of magnetic field lines around the magnetic X-point, destroying the last confinement surface (magnetic separatrix surface) in a diverted tokamak plasma. In this work we implement a passive tracer particle diagnostic to study plasma transport in turbulent homoclinic tangle structure. Turbulent electric and magnetic fields obtained from the total-f XGC gyrokinetic simulations are used to push tracer particles. Particle and energy transport by the homoclinic tangle in present tokamaks will be compared with those in fusion power production ITER plasma. Implication to diverter heat-load footprint will be discussed.