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The code GIST (Geometry Interface for Stellarators and Tokamaks) has been designed to provide the nonlinear gyrokinetic solver GENE (also GS2) with the necessary geometric information, in order to perform simulations in an arbitrary toroidal plasma with closed flux surfaces. GIST reads in a wout.txt file from the VMEC equilibrium code (at present the versions 6.90, 8.00, 8.46 up to 8.50 are supported) or an EFIT file for tokamak applications. Based on this information, GIST generates the geometry either for a flux-tube (a computational box surrounding a single magnetic field line on a prescribed flux surface) or an ensemble of tubes covering a selected magnetic surface (to be used with the full-surface GENE code). GIST is extensively documented, maintained under subversion (svn) control and freely available through contact (currently operating at 8 universities or research labs).
Following is sample GIST output for W7-X (left) and QUASAR normalized for GENE:
Bad (negative) and good curvature
Metric element g^11
Metric element g^22