DOE funds $21 million to advance diagnostics on the flagship facility at PPPL

The U.S. Department of Energy (DOE) has awarded $21 million in funding for collaborators to install and operate new scientific instruments on the flagship fusion facility at the DOE’s Princeton Plasma Physics Laboratory (PPPL). The five-year award for state-of-the-art diagnostics on the National Spherical Tokamak Experiment-Upgrade (NSTX-U) will provide funding “to probe key physics problems, validate sophisticated computer models, and chart a path to the next stage of fusion energy research,” the DOE said.

The support brings experts from 10 institutions around the country to augment the capabilities of diagnostics on the flagship experiment. The facility is in a repair period that is expected to last until May 2021, as the early date, or July 2022, as the late one.

“This funding is good news that adds real value,” said physicist Brent Stratton, who heads diagnostic operations on NSTX-U. “The funded diagnostics add considerable measurement capability and are being done by top-level experts,” Stratton said.

Among the collaborators is Egemen Kolemen, an assistant professor in Princeton University’s Department of Mechanical and Aerospace Engineering who leads a team that has been developing instruments for PPPL. Kolemen plans to bolster a system called Thomson scattering to enable it to detect and allow real-time control of the temperature and related key properties of the plasma on NSTX-U that fuels fusion reactions.

Fusion, the power that drives the sun and stars, combines light elements in the form of plasma — the state of matter composed of free electrons and atomic nuclei that makes up 99 percent of the visible universe — to generate massive amounts of energy. Scientists around the world are seeking to capture and control fusion energy to create a virtually inexhaustible supply of safe and clean power to generate electricity.

Research on the NSTX-U, a spherical tokamak (ST) that is shaped like a cored apple rather than the doughnut-like shape of conventional tokamaks, has shown evidence that it can confine plasma energy under reactor conditions better than that of conventional tokamaks. “Research on STs will not only inform the design of next-step devices, but may provide a compact design path for future fusion reactors,” the DOE’s call for collaborations said.

The new funding derives from a five-year plan for the NSTX-U that PPPL physicist Stan Kaye, who heads research on the facility, put together with PPPL managers and researchers earlier this year. “The plan lays out the plasma measurements we will need and what it will take to achieve these measurements,” Kaye said. “The funded diagnostics are consistent with our plan, and they will be key to helping us achieve our research objectives.”

The new funding accompanies the increasingly advanced modeling of fusion plasmas, said Chris Fall, Director of the DOE’s Office of Science. “One of the most important developments in fusion energy research in recent years has been the growing use of sophisticated computer modeling and simulation to better understand the behavior of plasmas and the operation of fusion reactors,” Fall said. “Validating these models in turn requires the development of more sophisticated diagnostic equipment, and this initiative will be a major contribution to that effort.”

PPPL, on Princeton University’s Forrestal Campus in Plainsboro, N.J., is devoted to creating new knowledge about the physics of plasmas — ultra-hot, charged gases — and to developing practical solutions for the creation of fusion energy. The Laboratory is managed by the University for the U.S. Department of Energy’s Office of Science, which is the single largest supporter of basic research in the physical sciences in the United States and is working to address some of the most pressing challenges of our time. For more information, visit energy.gov/science.