Current PPPL research includes access to a powerful new computer that will greatly expand the Laboratory’s platform for codes that analyze fusion experiments. PPPL scientists and engineers will share this computer with Princeton University, which has installed it on the Forrestal campus adjacent to PPPL. Also underway is the world’s first exploration of permanent magnets, like those on refrigerators but much more powerful, to create the complex magnetic fields that twisty stellarator fusion devices use to confine and control fusion plasmas. Such magnets aim to dramatically simplify stellarator design and construction. We will keep you updated on these projects throughout the year and be sure to check back with Quest in the summer of ’22 to see how these developments are coming along.

Stellar, a computing cluster that Princeton University has installed in its High-Performance Computing Research Center, will sharply advance research at PPPL to bring to Earth the fusion energy that powers the sun and stars. The cluster, which the Laboratory will share with a broad range of University departments, will be available to the entire PPPL scientific community, including engineers.

“Stellar will greatly expand our computing capacity,” said Bill Dorland, associate director for computational science at PPPL. “We’ll now be able to do more computations, and make more calculations, to figure out the physics and engineering problems that we work on.”

Stellar complements Traverse, the high-performance computing cluster installed in 2019 with graphics processing units (GPUs) that facilitate artificial intelligence. “Stellar provides leading-edge capacity for those codes that can’t run on GPUs,” said Curt Hillegas, associate chief information officer for Princeton University’s Office of Information Technology and the Princeton Institute for Computational Science and Engineering (PICSciE). “Think of Traverse as the place to go for GPUs,” added Bill Wichser, PICSciE’s director for advanced systems and data storage. “Codes that don’t use GPUs run on clusters like Stellar.”

The new high-performance computer will provide an integrated environment for whole-device modeling of plasma systems, and also serve as a robust development platform for the codes and calculations that require the most powerful computers in the world, such as the exascale computers that the U.S. Department of Energy sponsors.

Stellar and Traverse facilitate mission-critical computations for U.S. Department of Energy-sponsored fusion science and engineering and provide critical capacity for the plasma physics community.

PPPL has the lead role in a grant worth $3 million in U.S. Department of Energy (DOE) Advanced Research Projects Agency-Energy (ARPA-E) funding for the design and construction of permanent magnets to facilitate the development of fusion energy. Such magnets, like those on refrigerator doors but far more powerful, could provide a highly innovative basis for simplifying stellarators — twisty facilities for experiments in producing fusion energy. Complementing the ARPA-E award for the three-year project is $1 million from the Fusion Energy Sciences office of the DOE Office of Science.

A key advantage of stellarators is their ability to run without the risk of damaging disruptions that must be carefully controlled in doughnut-shaped fusion facilities called tokamaks. However, the design of intricately twisting stellarators has held back their development.

“If we succeed, this project will provide the basis for an attractive new type of stellarator that doesn’t use intricate and expensive magnetic coils,” said PPPL physicist David Gates, who leads the team that developed the ARPA-E proposal and who will head the design of the magnets and will measure the magnetic field that the completed work produces.

PPPL will develop the magnets in partnership with SABR Enterprises, a North Andover, Massachusetts, company that specializes in constructing permanent magnet assemblies. Assisting the design will be Auburn University, which has a small stellarator program of its own.

For Gates, a simplified stellarator could become an attractive candidate for a fusion energy pilot plant, which several national studies in 2020 and 2021 have called for. “We hope this project will be the start of a program based on permanent magnets,” he said, “a program that will take the risk out of designing and building these machines.”