Maryland today | UMD scientist helps fuel hopes for nuclear fusion

The article by lead author Matt Landreman, research associate at UMD’s Institute for Applied Electronics and Physics Research and co-author Elizabeth Paul Ph.D. ’20, a postdoctoral fellow at Princeton University at the U.S. Department of Energy’s Princeton Plasma Physics Laboratory (PPPL), details how to more precisely shape the enveloping magnetic fields within the device to create an unprecedented ability to hold fusion fuel together.

“The key was to develop software that lets you try new design methods quickly,” Paul said.

Stellarators, invented by Princeton astrophysicist and PPPL founder Lyman Spitzer in the 1950s, have long been upstaged by another class of devices called “tokamaks” in the global quest to produce fusion power. controlled. But recent developments in labs around the world have created a renewed interest in winding machines.

Fusion creates vast energy throughout the universe by combining light elements in the form of plasma, the hot, charged state of matter composed of free electrons and atomic nuclei (or ions) that make up 99% of the visible universe. Well-functioning Stellarators could produce lab versions of the process without risking the damaging disruptions faced by more widely used tokamak fusion facilities.

However, torsion magnetic fields in stellarators were less effective at confining plasma trajectories than symmetric donut-shaped fields in tokamaks, causing a large and sustained loss of the extreme heat needed to bring ions together to release fusion energy. Additionally, the complex coils that produce the star fields are difficult to design and build.

The new breakthrough produces so-called “quasisymmetry” in stellarators, nearly matching the symmetrical field-containment capability of a tokamak.

While scientists have long sought to produce near-symmetry in torsional stellarators, the new research is developing a trick to create it almost precisely. The trick uses new open-source software called SIMSOPT (Simons Optimization Suite) which is designed to optimize stellarators by slowly refining the simulated plasma boundary shape that delineates magnetic fields.

“The ability to automate things and quickly try things out with this new software makes those setups possible,” Landreman said.

Scientists could also apply the results to studying astrophysical problems, he said. In Germany, a team is developing a quasi-symmetrical stellarator to confine and study antimatter particles like those found in space.

“It’s exactly the same challenge as with the merger,” Landreman said. “You just have to make sure the particles stay contained.”

This article is based on a press release from the U.S. Department of Energy’s Princeton Plasma Physics Laboratory.