freegs4e 0.2.0

Free boundary tokamak plasma equilibrium Grad-Shafranov solver for time evolution

FreeGS4E: Free boundary Grad-Shafranov solver for time evolution

FreeGS4E is a package based on FreeGS, which calculates plasma equilibria for tokamak fusion experiments by solving the free boundary Grad-Shafranov equation. FreeGS4E is forked from FreeGS 0.6.1 and includes some performance optimisations that may also limit the use cases.

The primary use case for FreeGS4E is to provide a fast equilibrium solver for the FreeGSNKE code. This has resulted in some changes to the FreeGS codebase that mean FreeGS4E is no longer a drop-in replacement for FreeGS. FreeGS4E is also not intended to be a standalone equilibrium solver, and some features have been removed to improve performance. Users looking for a static equilibrium solver should use FreeGS.

Installing

FreeGS4E is available on PyPI and can be installed with pip:

pip install freegs4e

To build from source:

1. Download this repository

   git clone https://github.com/freegs4e/freegs4e
   

2. Install with pip

   cd freegs4e
   pip install .
   

Documentation

The FreeGS manual is in the docs subdirectory.

Examples

The Jupyter notebooks contain examples with additional notes

• MAST-example.ipynb

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

Contributing

To install FreeGS4E for development, clone the repository and install the package in editable mode with the development dependencies:

git clone https://github.com/freegs4e/freegs4e
cd freegs4e
pip install -e ".[dev]"

Changes to the main branch must be made through pull requests.

If you don't have write access to the repository, pull requests through GitHub forks are welcome.

Pre-commit hooks are used to ensure code quality. To install the pre-commit hooks, run:

pre-commit install

License

Copyright 2024 Nicola C. Amorisco, George K. Holt, Adriano Agnello, and other contributors.

FreeGS4E is licensed under the GNU Lesser General Public License version 3. The license text is included in the file LICENSE.

The license text for FreeGS is reproduced below:

Copyright 2016-2021 Ben Dudson, University of York, and other contributors.
Email: [e-mail]

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/>.

References

• YoungMu Jeon, Development of a free boundary Tokamak Equlibrium Solver arXiv:1503.03135
• S.Jardin "Computational Methods in Plasma Physics" CRC Press

Versions

0.1.0