pyrokinetics.equilibrium.geqdsk.EquilibriumReaderGEQDSK

pyrokinetics.equilibrium.geqdsk.EquilibriumReaderGEQDSK#

class pyrokinetics.equilibrium.geqdsk.EquilibriumReaderGEQDSK[source]#

Bases: FileReader

Class that can read G-EQDSK equilibrium files and return Equilibrium objects. Users are not recommended to instantiate this class directly, and should instead use the functions read_equilibrium or Equilibrium.from_file. Keyword arguments passed to those functions will be forwarded to this class.

Here we assume the convention COCOS 1 [Sauter & Medvedev, 2013]. However, EFIT uses COCOS 3, and other codes may follow other standards.

Some G-EQDSK files may not read correctly, as it is not possible to fit a closed contour on the Last Closed Flux Surface (LCFS). In these cases, the user may provide the argument psi_n_lcfs=0.99 (or something similarly close to 1) which adjusts the \(\psi\) grid so that only values in the range \([\psi_\text{axis},\psi_\text{axis}+0.99(\psi_\text{LCFS}-\psi_\text{axis})]\) are included.

It is not possible to determine the coordinate system used by a G-EQDSK file from its own data alone. By default, we assume that the toroidal angle \(\phi\) increases in an anti-clockwise direction when the tokamak is viewed from above. If the G-EQDSK file originates from a code that uses the opposite convention, the user should set clockwise_phi to True. Alternatively, if the COCOS convention of the G-EQDSK file is known, this should be supplied to the optional cocos argument.

See also

Equilibrium

Class representing a global tokamak equilibrium.

read_equilibrium

Read an equilibrium file, return an Equilibrium.

__init__()#

Methods

__init__()

read_from_file(filename[, psi_n_lcfs, ...])

Read in G-EQDSK file and populate Equilibrium object.

verify_file_type(filename)

Quickly verify that we're looking at a GEQDSK file without processing

Attributes

file_type

file_type: ClassVar[str] = 'GEQDSK'#
read_from_file(filename, psi_n_lcfs=1.0, clockwise_phi=False, cocos=None, a_minor_tolerance=0.05)[source]#

Read in G-EQDSK file and populate Equilibrium object. Should not be invoked directly; users should instead use read_equilibrium.

Parameters:

  • filename (PathLike) – Location of the G-EQDSK file on disk.

  • psi_n_lcfs (float, default 1.0) – Adjust which flux surface we consider to be the last closed flux surface (LCFS). Should take a value between 0.0 and 1.0 inclusive.

  • clockwise_phi (bool, default False) – Determines whether the \(\phi\) grid increases clockwise or anti-clockwise when the tokamak is viewed from above.

  • cocos (Optional[int]) – If set, asserts that the GEQDSK file follows that COCOS convention, and neither clockwise_phi nor the file contents will be used to identify the actual convention in use. The resulting Equilibrium is always converted to COCOS 11.

  • a_minor_tolerance (Optional[float]) – Maximum allowed relative tolerance on calculated a minor and the extrapolated a minor from inner surfaces to catch cases where divertor legs are in the contour fit for the LCFS

Return type:

Equilibrium

verify_file_type(filename)[source]#

Quickly verify that we’re looking at a GEQDSK file without processing

Return type:

None

Parameters:

filename (PathLike | str)

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