Set of functions and script used to calculate VMEC fixed-boundary equilibrium force error for Panici 2022

Installation

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• clone this repository

• Add this folder (VMECerror) and the subfolders VMECerror/plotting and VMECerror/fxns to your MATLAB path in order to run the scripts here and in the Zenodo files for the Panici 2022 paper.

Must also have matlabVMEC cloned locally and added on the MATLAB path

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force_error.m is the main script which will read in the data from the VMEC output files (wout) and get the R,Z,lambda fourier series coefficients, and calculate the necessary B,J and derivatives for findinf the force error.

debug_plot_quants.m plots quantities and compares them to what matlabVMEC calculates. Uncomment lines to compare different quantities. In these plots, "VMEC" labelled quantities are quantitites found using the fourier series coefficients from the VMEC wout file for that quantity (like bsupumnc, jcurrumnc for B^u and J^u), while the quantities labelled "my XX" are found from starting with just R,Z,and lamba calculated from the VMEC wout file and then multiplying them together in real space.

example.m shows using the scripts to calculate force error FSA for an example VMEC equilibrium