Air-core solenoid DC magnetics QuickField JSON Lines files

Geometry assumptions:
- Axisymmetric model: x = solenoid axis, y = radius, y >= 0 only.
- Coil winding region: x = -10..+10 mm, radius = 5..10 mm.
- Surrounding air boundary: semicircular domain radius 100 mm.
- Current source: total coil current/ampere-turns entered as 100 A using the coil block label.

Run air_core_solenoid_dc.qfp with ProblemBuilder from this folder.
