Events Calendar

A review of the stellarator concept: from Spitzer to W7-X

Dr. Elizabeth J. Paul; Department of Astrophysical Sciences, Princeton University

26 OCT 2021: Physics and Astronomy Colloquium

3:30pm, Online via Zoom

Zoom Link: https://uiowa.zoom.us/j/94392147007

Meeting ID: 943 9214 7007, No passcode

A stellarator confines plasma using non-axisymmetric magnetic fields for fusion energy sciences as well as the study of non-neutral and pair plasmas. This concept provides a promising route to steady-state fusion energy, given its ability to operate without driving a large current in the plasma. While the stellarator was invented 70 years ago by Lyman Spitzer, much of the effort of the magnetic confinement community has instead been focused on the axisymmetric tokamak, despite some potential drawbacks due to its reliance on plasma current for confinement. More recently, theoretical and engineering advances have enabled a renaissance for the stellarator. While the presence of an ignorable coordinate in axisymmetric devices yields integrability of particle orbits, stellarators can now be designed with "quasisymmetry" to preserve some of the benefits of axisymmetry. The resurgence of the stellarator concept is evidenced by the success of the W7-X experiment, the largest stellarator which became operational in 2015, in addition to several upcoming experiments. I will provide a tour of concepts and design principles that have enabled excellent stellarator confinement and point toward open questions and challenges in stellarator physics.