Single-Stage Stellarator Optimization: Combining Coils with Fixed Boundary Equilibria

TL;DR

This paper presents a new single-stage optimization method for stellarator design that simultaneously optimizes plasma boundary and coil shapes, improving efficiency and results over previous two-stage methods.

Contribution

It introduces a computationally efficient approach that combines plasma and coil optimization using fixed-boundary equilibria, applicable to various plasma scenarios.

Findings

Outperforms previous 2-stage methods in plasma objective values

Demonstrates effectiveness on simple and complex stellarator geometries

Applicable to vacuum and finite plasma pressure scenarios

Abstract

We introduce a novel approach for the simultaneous optimization of plasma physics and coil engineering objectives using fixed-boundary equilibria that is computationally efficient and applicable to a broad range of vacuum and finite plasma pressure scenarios. Our approach treats the plasma boundary and coil shapes as independently optimized variables, penalizing the mismatch between the two using a quadratic flux term in the objective function. Four use cases are presented to demonstrate the effectiveness of the approach, including simple and complex stellarator geometries. As shown here, this method outperforms previous 2-stage approaches, achieving smaller plasma objective function values when coils are taken into account.