State-of-the-art computer codes and world-class expertise at PPPL will provide four of the first 12 year-long collaborations under the newly created Innovation Network for Fusion Energy (INFUSE) program. The public-private partnerships, funded by the U.S. Department of Energy Office of Science, are intended to speed the development on Earth of the fusion energy that powers the sun and stars.
Organizing the merit-based review of industry proposals were INFUSE Director Dennis Youchison of Oak Ridge National Laboratory and PPPL physicist Ahmed Diallo, INFUSE deputy director. The winning proposals, which are subject to a successful negotiation of a Cooperative Research and Development Agreement (CRADA) between the companies and the laboratory, will collaborate with PPPL on projects ranging from simulation of fast ions produced by fusion reactions to development of a switch for a device combining magnetic and inertial fusion.
These companies will partner with PPPL and the physicists with whom they will collaborate:
TAE Technologies. A private company working toward development of a fusion reactor based on the field-reversed configuration (FRC) concept. The company will work with PPPL physicist Elena Belova and the advanced code that she has developed to study the combined effects of neutral beam injection (NBI) and rotation control methods on FRC global stability. In TAE experiments, NBI and rotation control are used to sustain and stabilize fusion plasma.
TAE Technologies. This TAE project calls for working with PPPL physicist Nicola Bertelli to perform high harmonic fast wave (HHFW) simulations for FRC plasmas and a University of California, Los Angeles (UCLA) device that has installed an HHFW antenna. These waves couple with electrons to heat and drive current in the plasma.
Commonwealth Fusion Systems. This company has grown from the Massachusetts Institute of Technology (MIT) to develop high-temperature superconducting magnets to build smaller, lower-cost fusion reactors. Commonwealth will collaborate with PPPL physicists Gerrit Kramer and Mario Podesta to use their PPPL codes to simulate how the configuration of magnetic coils will affect the confinement of fast particles produced by fusion reactions.
HelicitySpace. A startup company that is developing a combined magnetic and inertial plasma confinement system to drive spacecraft and generate electricity. The company is working with PPPL engineer Clement Bovet to analyze several powering architectures and switch technologies to meet the physics requirements for an experiment.
All INFUSE partnerships will last one year.
Rajesh Maingi, a world-renowned expert on the physics of plasma, has been named to co-lead a national program to unify research on liquid metal components for future tokamaks, doughnut-shaped fusion facilities. Maingi, who heads research on boundary physics and plasma-facing components at PPPL, will coordinate the three-year project in conjunction with Oak Ridge National Laboratory and the University of Illinois at Urbana-Champaign.
“It’s a pleasure to be offered the opportunity to do this,” said Maingi, whose current roles include serving as principal U.S. investigator for liquid lithium and impurity powder experiments on the Experimental Advanced Superconducting Tokamak (EAST) in China. “It will be a lot of work but liquid metal could prove essential for next-generation tokamaks.”
The program aims to develop the strategy for a liquid metal plasma-facing component for a future fusion facility, such as a fusion nuclear science facility to test fusion components, or a compact pilot power plant. The strategy will focus on coating a part called the divertor, which exhausts waste heat from a tokamak, with flowing liquid lithium — a silvery metal that the U.S. leads the world in developing as a plasma-facing component.
Such coating would protect the divertor from extreme heat and, under certain conditions, could largely prevent the recycling of material dislodged from the divertor back into the plasma to cool it down. The coating has also been shown to mitigate or even eliminate edge localized modes (ELMs), sudden bursts of heat that can damage a tokamak’s walls.
The process is also under development at the recently upgraded Lithium Tokamak Experiment (LTX) at PPPL, now known as the Lithium Tokamak Experiment-β, and has been tested in a preliminary manner at the PPPL National Spherical Torus Experiment (NSTX).
The nationwide program will examine key technology and science issues associated with the application of flowing liquid lithium to a tokamak divertor. Longer-term goals beyond three years include the evaluation of other liquid metal plasma-facing components if studies identify difficult or insurmountable challenges with lithium, and a plan to build and test components in present-day tokamaks. “As we look forward to next-generation machines, the need for liquid metal only appears to be growing stronger,” Maingi said.
Low-temperature plasma, a rapidly expanding source of innovation in fields ranging from electronics to health care to space exploration, is a highly complex state of matter. So complex that PPPL has teamed with Princeton University to become home to a collaborative facility open to researchers from across the country to advance the understanding and control of this dynamic physical state.
The new unit, called the Princeton Collaborative Research Facility on Low Temperature Plasma, opens the extensive diagnostic and computational resources at PPPL and Princeton to the academic, scientific and industrial communities. More than 40 researchers are estimated to be interested in topics that the facility will explore, said PPPL physicist Yevgeny Raitses, principal investigator of the new facility and head of the PPPL Laboratory for Plasma Nanosynthesis, which pioneers research on low-temperature plasma.
Raitses and physicist Igor Kaganovich, deputy head of the PPPL Theory Department, have long extended the outreach of low-temperature plasma research. Over the past 10 years they have collaborated with companies on topics ranging from the fabrication of microchips to the production of medical treatments to the development of a power switch to modernize the electric grid.
Heading the Princeton University team will be physicists Mikhail Shneider, an expert in plasma physics, fluid dynamics and non-linear optics, who will serve as co-principal investigator. Arthur Dogariu, who pioneered several advanced optical diagnostic techniques, will lead the collaborative center’s experimental efforts at Princeton
The total venture will be part of the Plasma Science and Technology Department that physicist Philip Efthimion heads at PPPL. “We’ll be offering our diagnostic and computer modeling tools to the research community and the private sector,” Efthimion said. “This will provide new opportunities to collaborate between the community and the private sector and to expand our research on low-temperature plasmas.”
How do you start on Earth a fusion reaction, the process that lights the sun and stars? Like lighting a match to start a fire, you first produce plasma, the gaseous state that fuels fusion reactions, and raise it to temperatures rivaling the sun in hundreds of milliseconds.
PPPL physicists, working with researchers at the Culham Centre for Fusion Energy (CCFE) in the United Kingdom, have constructed a simulation framework for developing and testing the plasma startup recipes for the National Spherical Torus Experiment-Upgrade (NSTX-U) at PPPL and the Mega Ampere Spherical Tokamak-Upgrade (MAST-U) at CCFE.
“This is a tool to help an operator design a successful startup recipe before sitting down in the driver seat at NSTX-U or MAST-U,” said physicist Devon Battaglia, who leads the team of operators on the NSTX-U experiment with findings reported in Nuclear Fusion.
The new simulation enables operators to quickly tune the pressure of the injected gas that breaks down into plasma with the evolution of the electric and magnetic fields, significantly reducing the time spent running experiments to find a recipe that works. Researchers derived and validated the models in the simulation framework against data collected from past experiments on the NSTX-U and its predecessor, and the predecessor of MAST-U.
“Plasma breakdown is a key milestone for MAST-U and Devon’s work provides valuable insight into the best route to achieve startup,” said physicist Andrew Thornton, lead operator at MAST-U. “Having Devon’s expertise on site when we restart will be immensely valuable as he has performed similar experiments on NSTX-U that can guide efforts on MAST-U.”