Radial electric field shear due to neoclassical effects in transport barriers

The Er×B flow shear is simulated with a fully kinetic five-dimensional neoclassical Monte Carlo simulation for JET and ASDEX Upgrade plasma edge conditions. Here, Er is the radial electric field and B is the magnetic field. It is shown that high enough shear for turbulence suppression can be driven at the Low (L) to High (H) transition conditions by pure neoclassical effects including ion orbit losses. Simulations indicate higher threshold shear for ASDEX Upgrade than for JET. Shear values are compared to different models and experimental results of critical shear, and isotope effect on shear is discussed. Formation of an internal transport barrier in FT-2 in the presence of lower hybrid waves is also studied