Augmented Lagrangian methods produce cutting-edge magnetic coils for stellarator fusion reactors

TL;DR

This paper introduces an augmented Lagrangian optimization method that efficiently generates superior magnetic coils for diverse stellarator fusion devices, overcoming previous challenges in nonconvex design landscapes.

Contribution

The work presents a novel augmented Lagrangian approach that effectively solves the complex coil optimization problem for stellarators, producing high-quality, Pareto-optimal coil solutions.

Findings

Generated coils outperform published sets in multiple cases

Method is effective across different stellarator symmetries

Achieved Pareto-optimal solutions in all tested scenarios

Abstract

Finding feasible coils for stellarator fusion devices is a critical challenge of realizing this concept for future power plants. Current design efforts struggle to navigate the highly nonconvex optimization landscape, spend considerable resources scanning the parameter space, and may produce suboptimal coils. In this work, we present an augmented Lagrangian approach to tackle the ill-posed problem of coil optimization. We illustrate its effectiveness and versatility by generating coils for five stellarators with very different symmetries and magnetic field shaping. In all cases, we find Pareto-optimal coil solutions that in various ways outperform published coil sets.