Stellaris: A high-field quasi-isodynamic stellarator for a prototypical fusion power plant

Abstract

Magnetic confinement fusion research has so far prioritized the tokamak concept, which presents greater design simplicity at the cost of control complexity in comparison to stellarators. Recent progress on high-temperature superconductors (HTS) has enabled a new generation of high-field tokamaks with more compact designs. However, the presence of large magnetic fields implies correspondingly large plasma currents, raising challenges regarding plasma stability. Meanwhile, key milestones have been reached in recent years by Wendelstein 7-X, the world's most advanced stellarator, and breakthroughs in computational optimization have enabled radically improved stellarator designs. In this paper, we present a concept for a new class of quasi-isodynamic (QI) stellarators leveraging HTS technology to overcome well-known challenges of a tokamak. This class of QI-HTS stellarators, labeled Stellaris, is shown to achieve an extensive set of desirable properties for reactor candidates simultaneously for the first time, offering a compelling path toward commercially viable fusion energy. We summarize a comprehensive reactor study, ranging from optimization of the plasma confinement region to first wall cooling, divertor considerations, blanket design, magnet quench safety, support structures, and remote maintenance solutions. Our results demonstrate that a coherent set of trade-offs between physics and engineering constraints can lead to a compelling stellarator design, suited for power plant applications. We anticipate that this work will motivate greater focus on QI stellarators, in both publicly and privately funded research.