OpenStar Technologies and Columbia Engineering Selected for DOE INFUSE Award to Design First Divertor for a Levitated Dipole
Columbia will validate advanced plasma simulation codes on OpenStar’s operating Junior experiment, then use them to design the exhaust system for OpenStar’s next machine
OpenStar Technologies and Columbia University’s engineering school have been selected by the U.S. Department of Energy’s Innovation Network for Fusion Energy (INFUSE) to design the first divertor for a levitated dipole fusion device. Managing heat and particle exhaust is one of the defining engineering challenges for any commercial fusion plant, and this project will shape how OpenStar’s machines tackle it.
The project is one of 28 selected in this year’s round of INFUSE, through which the DOE Office of Science is awarding $8.5 million to partnerships between U.S. fusion companies and DOE national laboratories or universities. It is one of two INFUSE awards OpenStar received this round through its U.S. subsidiary, OpenStar USA, alongside a plasma diagnostics project with the University of California San Diego.
The levitated dipole confines plasma with a single superconducting magnet floating inside a vacuum chamber, with no physical support. This architecture offers significant engineering simplifications and inherently stable plasma physics. OpenStar built its prototype, Junior, and achieved first plasma within two years. They continue to run experiments at its New Zealand facility. Junior is one of very few levitated dipoles operating in the world, and the platform this project is built on.
“Dipoles, like Earth’s magnetic field, are the most common natural environment that confines plasmas magnetically,” said Dr. Christopher Hansen, Research Scientist at Columbia Engineering. “Working together with OpenStar we will investigate how to extend our basic physics knowledge to modeling tools, enabling robust understanding and engineering of levitated dipoles for fusion energy.”
Every magnetic confinement fusion device must remove the heat and particles escaping the plasma edge before they damage the surrounding materials. Toroidal magnetic confinement devices do this with a divertor, which uses magnetic fields to steer that plasma onto dedicated targets, where it cools and is pumped out as exhaust. The divertor’s placement and performance shape component lifetimes, maintenance intervals and what a commercial plant costs to run. No divertor has yet been designed for a levitated dipole. Its unique geometry demands models beyond conventional approaches, but it also gives designers far more freedom over where a divertor goes and how it works.
“The magnetic dipole is an elegant and remarkably simple fusion concept that remains largely unexplored,” said Prof. Ben Zhu, Assistant Professor of Applied Physics and Applied Mathematics at Columbia Engineering. “This project gives us the opportunity to work with OpenStar on the particle and heat exhaust processes in a dipole configuration. A viable exhaust solution is among the most pressing challenges facing any fusion energy system, so what we learn here will contribute directly to the broader pursuit of commercial fusion power.”
The project builds on an existing collaboration and brings the levitated dipole back to Columbia, which ran the original Levitated Dipole Experiment (LDX) with MIT. At OpenStar, the project is led by Dr. Jerome Guterl, Principal Scientist, and Dr. Darren Garnier, Chief Science Officer, who served as Columbia’s chief experimentalist on LDX. At Columbia Engineering, the team is led by Zhu and Hansen, lead developer of the Open FUSION Toolkit, which includes TokaMaker.
Columbia will apply TokaMaker alongside Hermes-3, an established open-source code for plasma edge modeling. Together they model the magnetic shape of the plasma and how heat and particles move at its edge. Over 12 months, the team will validate both against measurements from Junior, then use them to determine the divertor’s shape and position and the loads it must handle.
The first application will be Tahi, OpenStar’s next machine, which targets fusion-relevant plasma conditions and is planned as a near-term neutron source for medical radioisotope production. The validated codes will then carry forward to every levitated dipole OpenStar builds, from isotope production to grid-scale fusion energy.
“In a levitated dipole, the X-point is a true null of the magnetic field, giving rise to novel edge plasma regimes. We are excited to combine Columbia’s outstanding expertise in edge plasma modeling with the lessons learned from decades of tokamak divertor research to develop power and particle exhaust solutions for Tahi and future dipoles,” said Guterl.
About OpenStar Technologies
OpenStar Technologies is a fusion company developing the full capability of the levitated dipole. Its approach uniquely enables abundant, economical neutron production, generating medical radioisotopes that support new diagnostics and therapies for cancer while advancing toward clean, limitless energy. The levitated dipole’s naturally stable plasma physics and modular architecture enable straightforward maintenance from prototype to plant scale.
About Columbia Engineering
Since 1864, the Fu Foundation School of Engineering and Applied Science at Columbia University has been a resource to the world for major advances in human progress. Today, Columbia Engineering is a global leader in engineering education, research, and impact. Located in the heart of New York City, the school convenes more than 270 faculty members and 6,000 undergraduate and graduate students to push the frontiers of knowledge and solve humanity’s most pressing problems.