The equilibrium fitting code EFIT was developed to perform magnetic and optionally kinetic-magnetic analyses for Doublet III. It can be run in either the fitting mode or the equilbrium mode. EFIT exists on the VAX's, the CRAYs, and various work stations. It can be run under either VMS or UNIX operating system with various grid sizes. In the equilibrium mode, it acts as an equilibrium solver. In the fitting mode, it performs magnetic fittings. The magnetic data needed for fitting can either be retrieved from the data bank directly or from an input file. There are two versions: EFIT for Doublet III (D-III) and EFITD for Doublet III D (DIII-D). Additionally, EFIT can also perform fixed boundary calculations. The stream functions used can be represented either in polynomial or in spline basis functions. Both single and double precision versions are available. The double precision versions are denoted by the suffix d.
The Green's tables are pre-computed and stored using the EFUND code. The standard set of tables uses a rectangular (R,Z) grid closely covering the DIII-D vessel. A set of tables covering a wider region of (R,Z) space can be used in place of the defaulted ones by redefining the table pointer using the command procedure EFIT:LARGE_TABLE before executing the EFIT code.
Additionally, EFIT can also carry out analysis including the effects of plasma toroidal rotation. Inputs are set in namelist INVT in file mode only.
For elongated plasmas, a stabilization option to allow the plasma to adjust vertically during iterations is also available.
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