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NetCDF Convention

Version 0.0.1

DEXTER reads equilibrium data from a netCDF file. The variables must follow the following conventions:

Scalars

  • baxis: The magnetic field strength on the magnetic axis \(B_0\) in \([T]\).
  • raxis: The horizontal position of the magnetic axis \(R_0\) \([m]\).
  • zaxis: The horizontal position of the magnetic axis \([m]\).
  • rgeo: The geometrical axis (device major radius) in \([m]\).

Note

For the normalizations, baxis and raxis should be used. They correspond to the center of the smallest flux surface. rgeo is characteristic of the device, while raxis depends on the configuration.

Coordinates

Note

If either psi_norm or psip_norm is missing from the netCDF file, it is calculated from the other by integrating \(q(\psi_p)\) or \(\iota(\psi)\) respectively. In the case that the calculated values are monotonic, the other flux can be used as a flux coordinate as well.

  • psip_norm: The poloidal flux coordinate \(\psi_p\) divided by \(2\pi\), in Normalized Units (consistent with the eqdisk files).
  • psi_norm: The toroidal flux coordinate \(\psi\) divided by \(2\pi\), in Normalized Units (consistent with the eqdisk files).
  • theta: The Boozer theta coordinate \(\theta_B\) in \([rads]\).
  • m: The poloidal mode number \(m\) (index coordinate).
  • n: The toroidal mode number \(n\) (index coordinate).

Not used in any calculations:

  • r_norm: The radial distance coordinate \(r\) in Normalized Units.

Variables

  • q: The safety factor \(q(\psi_p)\).
  • g_norm: The toroidal plasma current \(g(\psi_p)\) in Normalized Units.
  • i_norm: The poloidal plasma current \(I(\psi_p)\) in Normalized Units.
  • b_norm: The magnetic field strength \(B(\psi_p, \theta_B)\) in Normalized Units.
  • alphas_norm: The harmonic amplitudes \(\alpha_{m,n}(\psi_p)\) in Normalized Units.
  • phases: The harmonic phases \(\phi_{m,n}(\psi_p)\) in \([rads]\).

Original SI data (not used in any calculations):

  • r: The radial distance coordinate \(r(\psi_p)\) in \([m]\).
  • g: The toroidal plasma current \(g(\psi_p)\) in \([T \cdot m]\).
  • I: The poloidal plasma current \(I(\psi_p)\) in \([T \cdot m]\).
  • b: The magnetic field strength \(B(\psi_p, \theta_B)\) in \([T]\).
  • jacobian: The Jacobian matrix \(J(\psi_p, \theta_B)\) in \([m/T]\).
  • alphas: The harmonic amplitudes \(\alpha_{m,n}(\psi_p)\) in \([m]\).
  • rlab: The lab horizontal coordinate \(R(\psi_p, \theta_B)\) in \([m]\).
  • zlab: The lab vertical coordinate \(Z(\psi_p, \theta_B)\) in \([m]\).
  • psip: The poloidal flux coordinate \(\psi_p\) in \([T \cdot m^2]\).
  • psi: The toroidal flux coordinate \(\psi\) in \([T \cdot m^2]\).

Attributes

Optional file attributes to avoid confusion.

  • description: A short description.
  • date: The file's creation date.
  • script: The script used to create the file.
  • version: The convention version, using Semantic Versioning.