This is FLUX, the Field Line Universal Relaxer.
FLUX is a prototype MHD solver that is currently able to find nonlinear force-free fields with an exactly specified topology in a quasi-static, infinitely conductive, low-beta medium. Unlike conventional extrapolation codes, FLUX accepts as input a collection of field line shapes that do not necessarily have physical meaning but that do have the correct topology that you want to study. The FLUX engine relaxes the position of those field lines until they approximate the physical force-free state with the same topology that you specified.
FLUX consists of two parts: a relaxation engine, written in C, and a control interface in Perl. The control interface is intended to be used with Perl Data Language (PDL). If you do not have PDL on your system, you can get it for free from http://pdl.perl.org. PDL compiles "out of the box" on most UNIX systems.
For more details see Lowder, Gilly, and DeForest 2024 or the FLUX wiki.
Instructions for installing FLUX on Linux or macOS machines can be found in the documentation folder.
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doc -- install guide and some documentation (see the wiki for more up-to-date information.)
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include -- 'c' header files (these get installed into $FL_PREFIX/include/flux/)
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lib -- the central libflux.a core simulation library (this gets installed into $FL_PREFIX/lib/)
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pdl -- PDL glue code and perl modules
- pdl/PDL -- PDL autoload subroutines
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py -- Python visualization and analysis tools
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t -- Test suite
Authors:
- Craig DeForest (SwRI)
- Charles Kankelborg (MSU)
- Derek Lamb (SwRI)
- Chris Lowder (SwRI)
- Chris Gilly (SwRI)
- Laurel Rachmeler (then at CU Boulder & SwRI)
- Alisdair Davey (then at SwRI)
Contributors (gratefully acknowledged):
- Nathan Schwadron
- Teddy Walls
- Christopher Plumberg
The authors gratefully acknowledge support from NASA's Living With A Star and Solar/Heliospheric Physics programs, the AFOSR, and from the Southwest Research Institute.