General Atomics Scientists Win Dawson Award, Help Prove a New Path Toward Fusion Energy

Novel research shows unconventional plasma shape could help solve key challenges for future fusion power plants

SAN DIEGO, Oct. 26, 2026 - Inside a tokamak, powerful magnetic fields are used to shape and control superheated plasma so fusion reactions can take place. But what if changing that shape could make a future fusion power plant work better?

A multi-institutional team of scientists from General Atomics, Columbia University, the University of Texas at Austin, UC San Diego and Lawrence Livermore National Laboratory has shown that a distinctive plasma shape known as negative triangularity could offer a new path toward practical fusion energy. The research has now earned one of the highest honors in plasma physics: the American Physical Society's John Dawson Award for Excellence in Plasma Physics Research.

"One of the biggest challenges for commercial fusion is achieving the plasma performance needed to generate power while keeping the heat reaching the machine's walls at manageable levels. This research explores how negative triangularity could help meet both demands," said Wayne Solomon, vice president of Magnetic Fusion Energy for General Atomics Energy Group. "Negative triangularity gives us another promising path to explore as we work toward practical fusion energy."

Most tokamaks are designed to hold plasma in a donut shape whose cross-section looks somewhat like the letter D, with the curved side facing outward, away from the donut hole. Scientists have spent decades refining this configuration because it can help plasma retain heat and achieve strong performance. But this positive triangularity configuration also creates challenges, particularly when it comes to managing the intense heat inside a future fusion power plant.

The negative triangularity concept takes a different approach. It reverses the traditional D shape, so the curved side faces inward toward the center of the tokamak. In experiments at the DIII-D National Fusion Facility in San Diego, researchers found that this configuration could maintain strong plasma performance while avoiding edge-localized modes, or ELMs, instabilities that can send large bursts of heat and particles toward the walls of a fusion device.

To test their concept, the team modified DIII-D. Portions of the machine's protective armor were replaced with specialized tiles designed for negative-triangularity operation. They then tested those changes in operating plasmas, moving the concept into a dedicated experimental campaign.

The work was built on earlier negative-triangularity research at DIII-D and other tokamaks and tested how far the concept could be pushed under conditions relevant to future fusion power plants. Al Hyatt, chief physics operator on the DIII-D team at General Atomics, led the development of control techniques needed to operate the tokamak in the new configuration. The results surprised even the researchers.

"The campaign was exhilarating. We produced high-performance plasmas on DIII-D for weeks without seeing a single ELM," said Kathreen Thome, a staff scientist at General Atomics and co-lead of the experimental campaign. "Negative triangularity is a potentially revolutionary way to design and operate a tokamak for fusion energy, and helping lead this effort to demonstrate its commercial potential was an extraordinary moment in my career."

The findings give scientists a promising option for addressing some of the toughest challenges facing commercial fusion. The work will continue at DIII-D, where the next phase includes plans for a divertor optimized specifically for negative-triangularity operation through a public-private collaboration with Kyoto Fusioneering. The new hardware will allow researchers to push the concept further, test it under increasingly relevant conditions and better understand its potential for future commercial fusion power plants.

General Atomics is the first fusion company in the United States, establishing its fusion research program in 1957. Since then, the company has led international fusion research, advancing plasma physics, high-field magnets and precision engineering. General Atomics operates the DIII-D National Fusion Facility for the U.S. Department of Energy, the nation's largest operating tokamak. GA scientists and engineers in San Diego collaborate with researchers around the world to solve challenging fusion energy problems and develop technologies needed to make commercial fusion power a reality.

About General Atomics

Since the dawn of the atomic age, General Atomics innovations have advanced the state of the art across the full spectrum of science and technology from nuclear energy and defense to medicine and high-performance computing. Behind a talented global team of scientists, engineers, and professionals, GA's unique experience and capabilities continue to deliver safe, sustainable, economical, and innovative solutions to meet growing global demands.

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Andrew James
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General Atomics Energy Group