Effect of magnetic field structure on collisional drift waves

A 3-field model for collisional drift waves, in the ballooning representation, for a low-pressure stellarator plasma is presented. The 3-field model, which includes the effects of a finite radial mode number (theta k), is solved as an initial-value problem along the magnetic field line. It is shown that for a stellarator with low global magnetic shear, theta k = 0 corresponds to the fastest linear growth rate. The effects of the magnetic field structure for the tokamak and stellarator configurations are discussed in a comparative way.