Time-Dependent Perpendicular Transport of Energetic Particles in Magnetic Turbulence with Transverse Complexity

The motion of energetic particles in magnetic turbulence across a mean magnetic field is explored analytically. The approach presented here allows for a full time-dependent description of the transport, including compound sub-diffusion. The first time it is shown systematically that as soon as there is transverse structure of the turbulence, diffusion is restored even if no Coulomb collisions are invoked. Criteria for sub-diffusion and normal Markovian diffusion are found as well.