Stellarator coils

Placeholder. This problem is here so the problem panel can be tried out. Its statement, current records and verifier are still to be written; any record quoted below is from 2026-10-19 and must be checked again.

Problem

Given a target plasma boundary, find closed coil curves, a few dozen Fourier coefficients each, whose Biot–Savart field is tangent to the boundary while length, curvature and coil spacing stay buildable. Scoring follows Princeton’s SIMSOPT and the ConStellaration benchmark; the target and the weights are still to be fixed.