Simulating Gyrokinetic Microinstabilities in Stellarator Geometry with GS2

TL;DR

This paper extends the gyrokinetic code GS2 to simulate microinstabilities in stellarator geometry, enabling more accurate modeling of plasma behavior in non-axisymmetric devices like NCSX.

Contribution

The extension of GS2 to non-axisymmetric stellarator geometry with electromagnetic effects and multiple trapped regions is a novel advancement.

Findings

GS2 simulations agree with FULL eigenvalue code within ~10%

Linear stability calculations successfully benchmarked for NCSX

Extension enables more accurate stellarator plasma modeling

Abstract

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%.