Applied Math Seminar

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Stellarator Optimization – an Overview

Speaker: Sophia Henneberg, MIT

Location: Warren Weaver Hall 1302

Date: Friday, May 1, 2026, 2:30 p.m.

Synopsis:

To achieve fusion, one can exploit the charged nature of plasma by using a magnetic field to confine it. There are two main approaches to magnetically confined fusion energy: The tokamak is an axisymmetric approach. This simplicity comes at a cost, since tokamaks require a current in the plasma to generate the required magnetic field. Stellarators, on the other hand,  are sometimes described as the “twisted cousins” of tokamaks because, since they are not limited to (approximately) axisymmetric equilibria and instead allow for fully three-dimensional (3D) shaping. This expanded design space offers a key advantage: it doesn’t rely on a net plasma current. As a result, stellarators can achieve steady-state operation and exhibit enhanced stability against current-driven instabilities.

However, these benefits do not automatically follow from any arbitrary 3D shape. Poorly optimized configurations can lead to degraded confinement and increased instabilities. To unlock the full potential of stellarators, their geometry must be carefully tailored through optimization.

This presentation provides an overview of stellarator optimization methods and selected computational tools that enable them. Topics include equilibrium codes, plasma boundary representation, coil and divertor optimization approaches and tools. We will also highlight open questions and active research areas that shape the future of stellarator design.