Free boundary Grad-Shafranov solver
This Python module calculates plasma equilibria for tokamak fusion experiments, by solving the Grad-Shafranov equation with free boundaries. Given a set of coils, plasma profiles and shape, FreeGS finds the currents in the coils which produce a steady-state solution in force balance.
Note This is a work in progress, and probably contains bugs. There is a feature wishlist in issues, suggestions and contributions welcome!
FreeGS is available on PyPI
$ pip install --user freegs
or clone/download this repository and run setup:
$ git clone https://github.com/freegs-plasma/freegs.git
$ cd freegs
$ python setup.py install --user
The manual is in the docs
subdirectory, and hosted here on readthedocs.
Unit tests use pytest so after installing, run with:
$ pytest
The tests are in the src/
subdirectory.
A convergence test is described in the manual. To run:
$ python test-convergence.py
The Jupyter notebooks contain examples wuth additional notes
There are also some Python scripts to run short tests and examples
$ python 01-freeboundary.py
This solves a free boundary problem, specifying the desired location of two X-points. Writes the equilibrium to a G-EQDSK file "lsn.geqdsk"
$ python 02-read-geqdsk.py
Reads in the file "lsn.geqdsk", inferring the coil currents from the plasma boundary and profiles in the G-EQDSK file.
$ python 03-mast.py
Calculates a double-null (CDND) equilibrium for MAST from scratch. Writes solution to G-EQDSK file "mast.geqdsk"
$ python 04-read-mast-geqdsk.py
Reads the file "mast.geqdsk", inferring the coil currents.
$ python 05-fixed-boundary.py
This example solves a fixed boundary problem, in which the square edges of the domain are fixed. The plasma pressure on axis and plasma current are fixed.
$ python 06-xpoints.py
This demonstrates the coil current control code, finding X-points, and marking core region These routines are used inside the free boundary solver
The "freegs" module consists of the following files:
Copyright 2016-2022 Ben Dudson, University of York, and other contributors.
Email: [email protected]
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
0.7.0 16th August 2022
0.6.1 11th February 2021
0.6.0 29th January 2021
0.5.0 25th March 2020
0.4.0 10th November 2019
0.3.0 28th July 2019
0.2.0 12th March 2019
freegs.fieldtracer