zontafil/symplectic-guiding-center

Symplectic integrator for non canonical guiding center and others

Symplectic Guiding Center

Integrator written in c++ for numerical simulations of physical systems, focused on the variational symplectic integration of the guiding center.

Other interators/system are implemented/possible.

warning

This code is not optimized and very, very, very slow. Don't try or think to use it in a production environment.

Documentation

For a theoretical background and an explanation of the different integrators, please read the thesis (doc/thesis.pdf) or the comments inside each class.

Prerequisites

• Boost and Boost.log
• gsl
• eigen3

Compile and run

Make sure you have a valid configuration (config.h) file (see the following section)

  make
  ./bin/symplectic

if you don't have make, just use:

  g++ -DBOOST_LOG_DYN_LINK -Wall -o bin/symplectic symplectic.cpp -lgsl -lgslcblas -lboost_log -lboost_log_setup -lpthread -lboost_thread

Configuration

See utils/configInterface.h for the structure of a valid configuration.

A valid config class must be put in ./config.h. To start, just copy an example configuration in examples/ to ./config.h.

The main configurable entities are Integrator (config variables "integrator", "auxiliary_integrator", "first_guess_integrator"), System (config variable "system") and EMField (config variable "emField").

Valid integrators:

• RK4 (explicit)
• VariationalMidpoint (implicit)
• SymplecticExplicit1 (explicit, system must be "GuidingCenter", DIM must be 8)
• SymplecticExplicit2 (explicit, system must be "GuidingCenter", DIM must be 8)
• SymplecticExplicit3 (explicit, system must be "GuidingCenter", DIM must be 8)
• SymplecticExplicit4 (explicit, system must be "GuidingCenter", DIM must be 8)
• SymplecticImplicit1 (implicit, system must be "GuidingCenter", DIM must be 8)
• symplecticSemiexplicitQin (implicit, system must be "GuidingCenter", DIM must be 8)
• SymplecticImplicit3D (implicit, system must be "GuidingCenter", DIM must be 6)

Valid systems

• GuidingCenter

Valid EM fields

• Tokamak
• ForceFree
• TwoDimField

symplectic-guiding-center's Issues

bug magnetic field expression tokamak case

Thank you very much for making the code available.

It seems that the expression for the y component of the magnetic field for the tokamak case is not consistent with the vector potential and the pdf documentation.