One-dimensional transport models with local and nonlocal lower-hybrid-drift waves in field-reversed configurations

The one-dimensional transport theory for field-reversed configurations has been reexamined taking into account global lower-hybrid-drift turbulence. Extending previous work for nonlocal electrostatic lower-hybrid-drift theory, the spatial character of lower-hybrid-drift eigenmodes have been determined in the separatrix region of a field-reversed configuration. Surprisingly, it has been found that the transport model based on the more comprehensive ‘‘global’’ theory of the lower-hybrid-drift theory results in transport coefficients which are very similar to those based on the simple ‘‘local’’ lower-hybrid-drift theory. The reason for this is as follows. The nonlocal theory of the lower-hybrid-drift predicts a sequence of eigenmodes with differing eigenvalues and spatial extent. It is found that if a particular eigenmode is considered and the radial points which mark its radial extent are noted, then the eigenfrequency and growth rate associated with that eigenmode will have approximately the same value as the frequency and the growth rate naively calculated on the basis of the local conditions at the radial edges of the eigenmode.