Date: 2026-09-05 Purpose: Bulk YBCO disk under a background-field pulse from a user-defined source.

What it shows

This is the disk_ramp case with a pulse instead of a ramp. The field rises to 1 T over 100 ms, holds for 100 ms, drops to zero, and the run continues for 300 ms. Screening currents remain in the disk after the field is removed.

src/bgpulse.cpp defines the waveform and is compiled into bgpulse.so. The background entry loads it with type : userdefined. Note the units key there: for a plugin source the dimension of the returned value comes from that key, never from an amplitude.

Files

file	role
disk.geo	geometry; mesh it with gmsh
src/bgpulse.cpp, src/CMakeLists.txt	user source plugin
input.conf	deck

Run

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

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

gmsh -3 disk.geo -o disk.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.