Date: 2026-09-05 Purpose: Three racetrack coils with a user-defined bulk material.

What it shows

Three racetrack coils, each containing a 19-tape thin-shell stack, are driven by independent ramps of about 28 to 30 kA. src/matlib.cpp defines the surrounding bulk material and builds it into usermat.so, which the materials section loads with a usermat entry. The tapes use the built-in YBCO power law. Use this deck as a template for a material that BELFEM does not provide.

data/ is on the plugin's include path as BELFEM_USER_DATA_DIR. It ships no tables; its README explains how to read measured properties from there.

Files

file	role
racetrackAssembly_*.geo	geometry; mesh it with gmsh
src/matlib.cpp, src/CMakeLists.txt	user material plugin
data/	tables for the plugin (empty)
input.conf	deck

Run

Build the plugin first; the deck loads src/build/usermat.so:

cd src && mkdir -p build && cd build
cmake -DBELFEM_DIR=/path/to/belfem .. && make
cd ../..

gmsh -3 racetrackAssembly_3coils_19tapes_r2-63.6_r2-58.22_r2-37.5_qcyl.geo \
     -o racetrackAssembly_3coils_19tapes_r2-63.6_r2-58.22_r2-37.5_qcyl.msh
../../build/bin/belfem                 # or mpirun -np 4 ../../build/bin/belfem

Shared launcher

../scripts/Allrun generates the mesh, chooses ranks and threads, and can submit to Slurm; ../scripts/Allclean removes run output. To use them from this directory, copy the two wrapper scripts Allrun and Allclean from examples/helix/ here and run ./Allrun (./Allrun --dry-run prints the plan first). If you copy this deck out of the tree, copy examples/scripts/ along with it and point the wrappers at its new location. The launcher does not build plugins; do that step by hand as described above. Per-deck settings go in a run.conf next to input.conf; see ../scripts/README.md.