API Documentation

Basis

`desc.basis.PowerSeries`(L[, sym])	1D basis set for flux surface quantities.
`desc.basis.FourierSeries`(N[, NFP, sym])	1D basis set for use with the magnetic axis.
`desc.basis.DoubleFourierSeries`(M, N[, NFP, sym])	2D basis set for use on a single flux surface.
`desc.basis.ZernikePolynomial`(L, M[, sym, ...])	2D basis set for analytic functions in a unit disc.
`desc.basis.FourierZernikeBasis`(L, M, N[, ...])	3D basis set for analytic functions in a toroidal volume.

Continuation

`desc.continuation.solve_continuation`(eqfam)	Solve for an equilibrium by continuation method.
`desc.continuation.solve_continuation_automatic`(eq)	Solve for an equilibrium using an automatic continuation method.

Derivatives

Note that the derivative module also exposes the Derivative class, which is an alias for AutoDiffDerivative if JAX is installed, or FiniteDiffDerivative if not.

`desc.derivatives.AutoDiffDerivative`(fun[, ...])	Computes derivatives using automatic differentiation with JAX.
`desc.derivatives.FiniteDiffDerivative`(fun[, ...])	Computes derivatives using 2nd order centered finite differences.

Equilibrium

`desc.equilibrium.Equilibrium`([Psi, NFP, L, ...])	Equilibrium is an object that represents a plasma equilibrium.
`desc.equilibrium.EquilibriaFamily`(*args)	EquilibriaFamily stores a list of Equilibria.

Examples

`desc.examples.get`(name[, data])	Get example equilibria and data.
`desc.examples.listall`()	Return a list of examples that DESC has.

Geometry

`desc.geometry.FourierRZCurve`([R_n, Z_n, ...])	Curve parameterized by fourier series for R,Z in terms of toroidal angle phi.
`desc.geometry.FourierXYZCurve`([X_n, Y_n, ...])	Curve parameterized by fourier series for X,Y,Z in terms of arbitrary angle phi.
`desc.geometry.FourierPlanarCurve`([center, ...])	Curve that lines in a plane.
`desc.geometry.FourierRZToroidalSurface`([...])	Toroidal surface represented by Fourier series in poloidal and toroidal angles.
`desc.geometry.ZernikeRZToroidalSection`([...])	A toroidal cross section represented by a Zernike polynomial in R,Z.

Grid

`desc.grid.Grid`(nodes[, sort])	Base class for collocation grids.
`desc.grid.LinearGrid`([L, M, N, NFP, sym, ...])	Grid in which the nodes are linearly spaced in each coordinate.
`desc.grid.QuadratureGrid`(L, M, N[, NFP])	Grid used for numerical quadrature.
`desc.grid.ConcentricGrid`(L, M, N[, NFP, ...])	Grid in which the nodes are arranged in concentric circles.

IO

`desc.io.InputReader`([cl_args])	Reads command line arguments and parses input files.
`desc.io.load`(load_from[, file_format])	Load any DESC object from previously saved file.

Objective Functions

`desc.objectives.AspectRatio`([eq, target, ...])	Aspect ratio = major radius / minor radius.
`desc.objectives.BootstrapRedlConsistency`([...])	Promote consistency of the bootstrap current for axisymmetry or quasi-symmetry.
`desc.objectives.CurrentDensity`([eq, target, ...])	Radial, poloidal, and toroidal current density.
`desc.objectives.Elongation`([eq, target, ...])	Elongation = semi-major radius / semi-minor radius.
`desc.objectives.Energy`([eq, target, bounds, ...])	MHD energy.
`desc.objectives.ForceBalance`([eq, target, ...])	Radial and helical MHD force balance.
`desc.objectives.GenericObjective`(f[, eq, ...])	A generic objective that can compute any quantity from the data_index.
`desc.objectives.HelicalForceBalance`([eq, ...])	Helical MHD force balance.
`desc.objectives.Isodynamicity`([eq, target, ...])	Isodynamicity metric for cross field transport.
`desc.objectives.MagneticWell`([eq, target, ...])	The magnetic well is a fast proxy for MHD stability.
`desc.objectives.MeanCurvature`([eq, target, ...])	Target a particular value for the mean curvature.
`desc.objectives.MercierStability`([eq, ...])	The Mercier criterion is a fast proxy for MHD stability.
`desc.objectives.ObjectiveFunction`(objectives)	Objective function comprised of one or more Objectives.
`desc.objectives.PlasmaVesselDistance`(surface)	Target the distance between the plasma and a surounding surface.
`desc.objectives.PrincipalCurvature`([eq, ...])	Target a particular value for the (unsigned) principal curvature.
`desc.objectives.QuasisymmetryBoozer`([eq, ...])	Quasi-symmetry Boozer harmonics error.
`desc.objectives.QuasisymmetryTwoTerm`([eq, ...])	Quasi-symmetry two-term error.
`desc.objectives.QuasisymmetryTripleProduct`([...])	Quasi-symmetry triple product error.
`desc.objectives.RadialForceBalance`([eq, ...])	Radial MHD force balance.
`desc.objectives.RotationalTransform`([eq, ...])	Targets a rotational transform profile.
`desc.objectives.ToroidalCurrent`([eq, ...])	Target toroidal current profile.
`desc.objectives.Volume`([eq, target, bounds, ...])	Plasma volume.

Optimize

`desc.optimize.Optimizer`(method)	A helper class to wrap several optimization routines.
`desc.optimize.fmintr`(fun, x0, grad[, hess, ...])	Minimize a scalar function using a (quasi)-Newton trust region method.
`desc.optimize.lsqtr`(fun, x0, jac[, args, ...])	Solve a least squares problem using a (quasi)-Newton trust region method.

Perturbations

`desc.perturbations.get_deltas`(things1, things2)	Compute differences between parameters for perturbations.
`desc.perturbations.perturb`(eq, objective, ...)	Perturb an Equilibrium with respect to input parameters.
`desc.perturbations.optimal_perturb`(eq, ...)	Perturb an Equilibrium with respect to input parameters to optimize an objective.

Plotting

`desc.plotting.plot_1d`(eq, name[, grid, log, ...])	Plot 1D profiles.
`desc.plotting.plot_2d`(eq, name[, grid, log, ...])	Plot 2D cross-sections.
`desc.plotting.plot_3d`(eq, name[, grid, log, ...])	Plot 3D surfaces.
`desc.plotting.plot_basis`(basis[, return_data])	Plot basis functions.
`desc.plotting.plot_boozer_modes`(eq[, log, ...])	Plot Fourier harmonics of \(\|B\|\) in Boozer coordinates.
`desc.plotting.plot_boozer_surface`(eq[, ...])	Plot \(\|B\|\) on a surface vs the Boozer poloidal and toroidal angles.
`desc.plotting.plot_boundaries`(eqs[, labels, ...])	Plot stellarator boundaries at multiple toroidal coordinates.
`desc.plotting.plot_boundary`(eq[, zeta, ...])	Plot stellarator boundary at multiple toroidal coordinates.
`desc.plotting.plot_coefficients`(eq[, L, M, ...])	Plot spectral coefficient magnitudes vs spectral mode number.
`desc.plotting.plot_coils`(coils[, grid, ax, ...])	Create 3D plot of coil geometry.
`desc.plotting.plot_comparison`(eqs[, rho, ...])	Plot comparison between flux surfaces of multiple equilibria.
`desc.plotting.plot_field_lines_sfl`(eq, rho)	Plots field lines on specified flux surface.
`desc.plotting.plot_fsa`(eq, name[, ...])	Plot flux surface averages of quantities.
`desc.plotting.plot_grid`(grid[, return_data])	Plot the location of collocation nodes on the zeta=0 plane.
`desc.plotting.plot_logo`([savepath])	Plot the DESC logo.
`desc.plotting.plot_qs_error`(eq[, log, fB, ...])	Plot quasi-symmetry errors f_B, f_C, and f_T as normalized flux functions.
`desc.plotting.plot_section`(eq, name[, grid, ...])	Plot Poincare sections.
`desc.plotting.plot_surfaces`(eq[, rho, ...])	Plot flux surfaces.

Profiles

`desc.profiles.PowerSeriesProfile`([params, ...])	Profile represented by a monic power series.
`desc.profiles.SplineProfile`([values, knots, ...])	Profile represented by a piecewise cubic spline.
`desc.profiles.MTanhProfile`([params, grid, name])	Profile represented by a modified hyperbolic tangent + polynomial.
`desc.profiles.ScaledProfile`(scale, profile, ...)	Profile times a constant value.
`desc.profiles.SumProfile`(profiles, *kwargs)	Sum of two or more Profiles.
`desc.profiles.ProductProfile`(profiles, *kwargs)	Product of two or more Profiles.

Transform

desc.transform.Transform(grid, basis[, ...])

Transforms from spectral coefficients to real space values.

VMEC

desc.vmec.VMECIO()

Performs input from VMEC netCDF files to DESC Equilibrium and vice-versa.