simsopt.mhd

Submodules

simsopt.mhd.boozer module

This module provides a class that handles the transformation to Boozer coordinates, and an optimization target for quasisymmetry.

class simsopt.mhd.boozer.Boozer(equil: simsopt.mhd.vmec.Vmec, mpol: int = 32, ntor: int = 32)

Bases: simsopt.core.optimizable.Optimizable

This class handles the transformation to Boozer coordinates.

A Boozer instance maintains a set “s”, which is a registry of the surfaces on which other objects want Boozer-coordinate data. When the run() method is called, the Boozer transformation is carried out on all these surfaces. The registry can be cleared at any time by setting the s attribute to {}.

get_dofs()
register(s: Union[float, Iterable[float]]) → None

This function is called by objects that depend on this Boozer object, to indicate that they will want Boozer data on the given set of surfaces.

Parameters

s – 1 or more surfaces on which Boozer data will be requested.

run()

Run booz_xform on all the surfaces that have been registered.

set_dofs(x)
class simsopt.mhd.boozer.Quasisymmetry(boozer: simsopt.mhd.boozer.Boozer, s: Union[float, Iterable[float]], m: int, n: int, normalization: str = 'B00', weight: str = 'even')

Bases: simsopt.core.optimizable.Optimizable

This class is used to compute the departure from quasisymmetry on a given flux surface based on the Boozer spectrum.

J() → Iterable

Carry out the calculation of the quasisymmetry error.

get_dofs()
set_dofs(x)
simsopt.mhd.boozer.closest_index(grid: Iterable[float], val: float) → int

Given a grid of values, find the grid point that is closest to an abitrary value.

Parameters

  • grid – A list of values.

  • val – We will return the index of the closest grid point to this value.

simsopt.mhd.spec module

This module provides a class that handles the SPEC equilibrium code.

class simsopt.mhd.spec.Residue(spec, pp, qq, vol=1, theta=0, s_guess=None, s_min=- 1.0, s_max=1.0, rtol=1e-09)

Bases: simsopt.core.optimizable.Optimizable

Greene’s residue, evaluated from a Spec equilibrum

J()

Run Spec if needed, find the periodic field line, and return the residue

get_dofs()
set_dofs(x)
class simsopt.mhd.spec.Spec(filename=None, exe='xspec')

Bases: simsopt.core.optimizable.Optimizable

This class represents the SPEC equilibrium code.

Philosophy regarding mpol and ntor: The Spec object keeps track of mpol and ntor values that are independent of those for the boundary Surface object. If the Surface object has different mpol/ntor values, the Surface’s rbc/zbs arrays are first copied, then truncated or expanded to fit the mpol/ntor values of the Spec object to before Spec is run. Therefore, you may sometimes need to manually change the mpol and ntor values for the Spec object.

get_dofs()
iota()

Return the rotational transform in the middle of the volume.

run()

Run SPEC, if needed.

set_dofs(x)
update_resolution(mpol, ntor)

For convenience, to save “.nml”

volume()

Return the volume inside the VMEC last closed flux surface.

simsopt.mhd.spec.nested_lists_to_array(ll)

Convert a ragged list of lists to a 2D numpy array. Any entries that are None are replaced by 0.

This function is applied to the RBC and ZBS arrays in the input namelist.

simsopt.mhd.vmec module

This module provides a class that handles the VMEC equilibrium code.

class simsopt.mhd.vmec.Vmec(filename=None, mpi=None)

Bases: simsopt.core.optimizable.Optimizable

This class represents the VMEC equilibrium code.

__repr__()

Print the object in an informative way.

aspect()

Return the plasma aspect ratio.

get_dofs()
get_max_mn()

Look through the rbc and zbs data in fortran to determine the largest m and n for which rbc or zbs is nonzero.

iota_axis()

Return the rotational transform on axis

iota_edge()

Return the rotational transform at the boundary

load_wout()
run()

Run VMEC, if needed.

set_dofs(x)
volume()

Return the volume inside the VMEC last closed flux surface.

Module contents