Merge branch 'master' into yge/tr_direct

CHANGELOG.md

@@ -2,6 +2,7 @@ Changelog
 =========
 
 New Features
+
 - Adds ``from_input_file`` method to ``Equilibrium`` class to generate an ``Equilibrium`` object with boundary, profiles, resolution and flux specified in a given DESC or VMEC input file
 - Adds function ``solve_regularized_surface_current`` to ``desc.magnetic_fields`` module that implements the REGCOIL algorithm (Landreman, (2017)) for surface current normal field optimization
     * Can specify the tuple ``current_helicity=(M_coil, N_coil)`` to determine if resulting contours correspond to helical topology (both ``(M_coil, N_coil)`` not equal to 0), modular (``N_coil`` equal to 0 and ``M_coil`` nonzero) or windowpane/saddle (``M_coil`` and ``N_coil`` both zero)
@@ -13,6 +14,10 @@ New Features
     * use of both this and the ``QuadraticFlux`` objective allows for REGCOIL solutions to be obtained through the optimization framework, and combined with other objectives as well.
 - Changes local area weighting of Bn in QuadraticFlux objective to be the square root of the local area element (Note that any existing optimizations using this objective may need different weights to achieve the same result now.)
 - Adds a new tutorial showing how to use``REGCOIL`` features.
+- Adds ``SurfaceQuadraticFlux`` objective which minimizes the quadratic magnetic flux through a ``FourierRZToroidalSurface`` object, allowing for optimizing for Quadratic flux minimizing (QFM) surfaces.
+- Allows ``ToroidalFlux`` objective to accept ``FourierRZToroidalSurface`` so it can be used to specify the toroidal flux through a QFM surface.
+- Adds ``eq_fixed`` flag to ``ToroidalFlux`` to allow for the equilibrium/QFM surface to vary during optimization, useful for single-stage optimizations.
+- Adds tutorial notebook showcasing QFM surface capability.
 
 
 Bug Fixes

desc/objectives/__init__.py

@@ -12,6 +12,7 @@
     PlasmaCoilSetMinDistance,
     QuadraticFlux,
     SurfaceCurrentRegularization,
+    SurfaceQuadraticFlux,
     ToroidalFlux,
 )
 from ._equilibrium import (