Results are presented from the 3-D non-local electromagnetic turbulence code BOUT and the linearized shooting code BAL for studies of turbulence in tokamak boundary plasmas and its relationship to the L-H transition, in a realistic divertor plasma geometry. The key results include: (1) the identification of the dominant resistive X point mode in divertor geometry; (2) turbulence suppression in the L-H transition by shear in the E × B drift velocity, ion diamagnetism and finite polarization; (3) the fact that calculated values of the thermal diffusivities such as χi are comparable to those inferred from the experimentally measured plasma density and temperature profiles. On the basis of simulation results, a parameterization of the transport is given that includes the dependence on the relevant physical parameters.
Nonlinear Magnetohydrodynamics