Estimating coil features from an equilibrium

Abstract: We present an explicit theoretical framework for constructing artificial modular coils based solely on equilibrium properties, achieved through the formulation of a current potential defined on flux surfaces. We demonstrate that key measures of coil complexity (particularly coil non-planarity) are strongly governed by local magnetic field properties and show promise as predictors for more realistic coil configurations. This approach provides both a pathway towards deeper understanding of equilibrium-coil relationships and a potential practical proxy for coil design.