Date: 2026-09-05 Purpose: Pancake coil sector with a Python-generated mesh.

What it shows

An eight-tape pancake coil wound 1.75 turns along a Lame spiral, represented by a 30-degree sector of a twelve-coil machine. The sector planes are periodic; the leads exit radially and end on the outer cylinder, where the stack end faces are the current terminals. The tapes use superox.hdf5, and a 10 kA sigmoid ramps over 10 s.

python/main.py generates the spiral, leads, air box, mesh, and matching topology section (pancake_topology.conf). Edit the parameters at the top of main.py to change the coil.

Files

file	role
python/main.py	mesh generator; run it from this directory
python/pancake/, python/mesh/	packages the generator uses
python/tests/	unit tests for the generator
input.conf	deck

Run

This deck ships no .geo. The mesh is built by a Python tool, which also prints the matching topology section for input.conf:

python3 python/main.py # writes the .msh into the current directory

../../build/bin/belfem # or mpirun -np 4 ../../build/bin/belfem

Run it from this directory so the mesh lands where input.conf expects it. The tool needs numpy, scipy, sympy and matplotlib, and calls the gmsh executable.

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.