CHEASE

The CHEASE code is an open source fixed-boundary equilibrium code described in the following publications:

1. H. Lütjens, A. Bondeson and O. Sauter, The CHEASE code for toroidal MHD equilibria, Comput. Phys. Commun. 97 (1996) 219
   BibTeX

   @article{Lutjens1996, abstract = {The CHEASE code (Cubic Hermite Element Axisymmetric Static Equilibrium) solves the Grad-Shafranov equation for toroidal MHD equilibria using a Hermite bicubic finite element discretization with pressure, current profiles and plasma boundaries specified by analytical forms or sets of experimental data points. Moreover, CHEASE allows the automatic generation of pressure profiles marginally stable to ballooning modes or with a prescribed fraction of bootstrap current. The code provides equilibrium quantities for several stability and global wave propagation codes.}, author = {Lutjens, H and Bondeson, A and Sauter, O}, issn = {0010-4655}, journal = {Computer Physics Communications}, number = {3}, pages = {219--260}, title = {{The CHEASE code for toroidal MHD equilibria}}, volume = {97}, year = {1996} }
2. H. Lütjens, A. Bondeson and A. Roy, Axisymmetric MHD equilibrium solver with bicubic Hermite elements, Comput. Phys. Commun. 69 (1992) 287
   BibTeX

   @article{Lutjens1992, abstract = {A numerical code using Hermite bicubic finite elements has been developed for the computation of axisymmetric magnetohydrodynamic (MHD) equilibria. The code provides a mapping to flux coordinates for MHD stability calculations. Several test cases are studied to show the convergence rate for the equilibrium. Convergence tests are also presented for the eigenvalues of the stability calculations when the equilibrium mesh is varied.}, author = {L{"{u}}tjens, H. and Bondeson, a. and Roy, a.}, file = {:Users/ffelici/Library/Application Support/Mendeley Desktop/Downloaded/L{"{u}}tjens, Bondeson, Roy - 1992 - Axisymmetric MHD equilibrium solver with bicubic Hermite elements.pdf:pdf}, journal = {Computer Physics Communications}, number = {2-3}, pages = {287--298}, title = {{Axisymmetric MHD equilibrium solver with bicubic Hermite elements}}, volume = {69}, year = {1992} }

License

The code is open source with Apache 2.0 license, see License

Contributing

You are very welcome to contribute to the code, see CONTRIBUTING.md

COordinate COnventionS

CHEASE uses COCOS=2 internally, but has COCOS_in and COCOS_out namelist variable to match to any COCOS index (see below)

Repository

CHEASE is presently maintained at https://gitlab.epfl.ch/spc/chease To get the latest version do: git clone https://gitlab.epfl.ch/spc/chease.git chease A list of tags and releases is maintained README_tags

Prior to November 2021, CHEASE was maintained on https://spcsvn.epfl.ch. The switch to SVN was made at SVN commit number 1368 corresponding to tag v12.18

Installation

A new file explaining how to install and run the make commands has been added: Make_README

GUI

There is a matlab GUI within the above release (in matlab directory) which is useful to get used to running CHEASE in matlab/CHEASEgui.m (see demos below)

PATH=$PATH:$HOME/bin  # in your .profile, .cshrc or .bashrc file (or equivalent)
cd $HOME/bin
$ ln –s .../chease/src-f90/chease .
$ ln –s .../chease/scripts_for_bin/o.chease_to_cols .
$ ln –s .../chease/scripts_for_bin/o.chease_rz_plasma_boundary_to_cols.pl .
$ ln –s .../chease/scripts_for_bin/o.chease_to_cols_v10.pl .
$ matlab -nodesktop # open matlab
>> addpath .../chease/matlab/CHEASEgui
>> CHEASEgui

chease > o.cheaseoutput
o.chease_to_cols   o.cheaseoutput   o.cheaseoutput.cols
matlab
>> addpath matlab/CHEASEgui
>> plotdatafile(' o.cheaseoutput.cols') % which will open a GUI to plot profiles

Instructions for using CHEASE with q profile input

New option for CHEASE with q profile in input: NSTTP = 5 You can test this option using:

  make test_chease_q

Then looking at the files in /tmp/$USER/nsttp_tests

Dependencies

CHEASEgui as well as read_eqdsk use extensively the cubic spline with smoothing package: interpos (http://spc.epfl.ch/interpos) which you might be interested in using as well (matlab, fortran, C, etc). You will need to sign a similar agreement.

References

• CHEASE website
• Notes on the CHEASE normalizations
• COCOS paper defining uniquely the multiple options for Coordinate COnventionS (by O. Sauter et S. Y Medvedev) (author version, journal version)
• CPO structure. CHEASE now uses the equilibrium structure originally proposed by the EU-ITM Task Force: CPO paper

Demos

• Using CamStudio, the following demo are available (.avi large files)
• Demo 1 (42MB) for getting started with CHEASEgui
• Demo 2 (20MB) to easily specify a reverse q profile

Contact person

Olivier Sauter, SPC-EPFL: olivier.sauter@epfl.ch