desc.vmec.VMECIO.load

classmethod VMECIO.load(path, L=None, M=None, N=None, spectral_indexing='ansi', profile='iota')Source

Load a VMEC netCDF file as an Equilibrium by fitting with Fourier-Zernike.

Loads in the VMEC netCDF file and loads the R, Z and Lambda Fourier coefficients, which from VMEC are given on each discrete flux surface in the VMEC solution. A Fourier-Zernike basis is then fit to these R, Z and Lambda Fourier coefficients to yield the DESC representation that most closely resembles the VMEC solution. Finally, the VMEC boundary is loaded and the DESC Equilibrium R,Z are constrained to match the given VMEC boundary.

NOTE: This is only a fit, so the DESC Equilibrium returned is not expected to be in force balance. It is recommended to solve the Equilibrium once loaded before using the Equilibrium for any analysis.

Parameters:

  • path (str) – File path of input data.

  • L (int, optional) – Radial resolution of the fit. Default determined by index.

  • M (int, optional) – Poloidal resolution of the fit. Default = MPOL-1 from VMEC solution.

  • N (int, optional) – Toroidal resolution of the fit. Default = NTOR from VMEC solution.

  • spectral_indexing (str, optional) – Type of Zernike indexing scheme to use. (Default = 'ansi')

  • profile ({"iota", "current"}) – Which profile to use as the equilibrium constraint. (Default = 'iota')

Returns:

eq (Equilibrium) – Equilibrium fit that resembles the VMEC data.

Notes

To ensure compatibility with different profile representations in VMEC, the resulting equilibrium will always have SplineProfile types for all profiles