Editing Stellarator (section)

=== Stellarator returns ===
As the problems with the tokamak approach grew, interest in the stellarator approach reemerged.<ref name="Clery2013"/> This coincided with the development of advanced [[computer aided design|computer aided]] planning tools that allowed the construction of complex magnets that were previously known but considered too difficult to design and build.<ref>{{cite web|url=https://projects.research-and-innovation.ec.europa.eu/en/horizon-magazine/twisting-design-fusion-reactor-thanks-supercomputers|title=Twisting design of fusion reactor is thanks to supercomputers|last=Bilby|first=Ethan|date=14 April 2016|website=Horizon: the EU Research & Innovation magazine|language=en|access-date=3 May 2024|archive-date=13 April 2024|archive-url=https://web.archive.org/web/20240413025231/https://projects.research-and-innovation.ec.europa.eu/en/horizon-magazine/twisting-design-fusion-reactor-thanks-supercomputers|url-status=live}}</ref><ref>{{cite web|url=https://newatlas.com/wendelstein7x-fusion-stellarator-plasma-tests/40014/|title=Wendelstein 7-x stellarator puts new twist on nuclear fusion power|last=Jeffrey|first=Colin|date=26 October 2015|website=New Atlas|language=en|access-date=22 December 2019}}</ref>

New materials and construction methods have increased the quality and power of the magnetic fields, improving performance. New devices have been built to test these concepts. Major examples include [[Wendelstein 7-X]] in Germany, the [[Helically Symmetric Experiment]] (HSX) in the US, and the [[Large Helical Device]] in Japan. W7X and LHD use [[superconducting magnet|superconducting magnetic coil]]s.

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The lack of an internal current eliminates some of the instabilities of the tokamak, meaning the stellarator should be more stable at similar operating conditions. On the downside, since it lacks the confinement provided by the current found in a tokamak, the stellarator requires more powerful magnets to reach any given confinement. The stellarator is an inherently steady-state machine, which has several engineering advantages.

In 2023 PPPL built an experimental device using mainly commercial components at a cost of $640,000. Its core is a glass vacuum chamber surrounded by a [[3D printing|3D-printed]] nylon shell that anchors 9,920 [[permanent magnets]]. Sixteen electromagnets wrap the shell.<ref>{{cite web |last=Clynes |first=Tom |date=28 October 2024 |title=Stellarators and AI: The Future of Fusion Energy Research – IEEE Spectrum |url=https://spectrum.ieee.org/the-off-the-shelf-stellarator |access-date=2024-12-09 |website=spectrum.ieee.org |language=en}}</ref>