  The nonlinear gyrokinetic code GS2 has been extended to treat
non-axisymmetric stellarator geometry. Electromagnetic perturbations and
multiple trapped particle regions are allowed. Here, linear, collisionless,
electrostatic simulations of the quasi-axisymmetric, three-field period
National Compact Stellarator Experiment (NCSX) design QAS3-C82 have been
successfully benchmarked against the eigenvalue code FULL. Quantitatively, the
linear stability calculations of GS2 and FULL agree to within ~10%.

Plasma Physics