Drift wave simulations in stellarator geometry

A model, based on gyro-kinetic ions and fluid electrons, to study drift waves in low-β [β=(kinetic pressure)/(magnetic pressure)] stellarator plasmas is presented. The model equations are written in straight-field-line coordinates and are valid for arbitrary, fully three-dimensional configurations with closed, nested magnetic surfaces. An implicit method, coupled with a subcycling technique for the electrons, is used to solve the time-dependent, along-the-field-line equations. Numerical calculations are carried out for a three-field-period toroidal heliac. The geometrical effects that enter the model equations are calculated and displayed in physical space using advanced visualization techniques.