New national facility at PPPL and Princeton University explores low temperature plasma for innovative uses

From plasma technologies to fight the COVID-19 pandemic to heat-resistant Earth reentry vehicles, U.S. researchers are exploring innovative projects at the new Princeton Collaborative Low Temperature Plasma Research Facility (PCRF). The joint venture of the U.S. Department of Energy’s (DOE) Princeton Plasma Physics Laboratory (PPPL) and Princeton University provides access to world-class diagnostics, computational tools, and expertise in plasma physics for characterizing low temperature plasmas (LTP) — a rapidly expanding source of innovation in fields ranging from electronics to health care to space exploration.

Impressive results

The year-old facility, formed from LTP laboratories at PPPL and the Department of Mechanical and Aerospace Engineering (MAE) at Princeton University, is preparing its second round of collaborative projects. “All of us at PCRF are very pleased with the impressive results of the first solicitation, which demonstrated a remarkable user demand for PCRF research resources and our expertise,” said PPPL physicist Yevgeny Raitses, principal investigator for the facility.

“We received 46 collaborative user proposals for experiments and modeling from academia, national labs and industry, both U.S. and international,” Yevgeny said. “Each went through internal and external review before 14 were selected, with a majority receiving supplemental funding from the DOE Office of Science. We also accepted five fast-track, less-than-two-week projects aimed at testing the ideas of prospective collaborators.”

Low temperature plasmas consist of atoms stripped of an outer electron and includes atomic nuclei, or ions, and neutral atoms and molecules. These plasmas take their name from the fact that while the electrons are as hot as tens of thousands of degrees, the rest of the constituents remain close to room temperature. Such plasmas are used in semiconductor manufacturing, material modification, and many other fields. These plasmas are distinct from the fusion plasmas in which the electrons and ions are heated to millions of degrees, which PPPL studies in the effort to capture and control for generating electricity the fusion energy that powers the sun and stars.

Plays many roles

Overseeing the new facility is the Plasma Science & Technology Department at PPPL headed by physicist Philip Efthimion. “Hosting national collaborative research centers is an important role for the DOE national labs,” Efthimion said. “PCRF is very important to PPPL because it plays many roles. It expands our expertise in low temperature plasma, supports our initiative in microelectronics, broadens our research base, and provides many opportunities for PPPL staff to collaborate with the low temperature plasma community at universities, industry, and other government research institutions.”

Here is a look at some current collaborations that PPPL and Princeton scientists are conducting in the new state-of-the-art facility:

• Mikhail Shneider, an MAE researcher and co-principal investigator of the PCRF, is exploring the breakdown of plasma in liquid with Texas A&M University-Kingsville (TAMU) in Kingsville, Texas. Such breakdown is crucial to the design of pulsed power systems that deliver high-voltage power for uses ranging from food processing to water contamination. “There are still missing links between the inception of the process and the formation of the first plasma channel,” said Shneider. “We and Prof. Xuewei Zhang of Texas A&M are conducting theoretical studies of the very initial stage of such breakdowns.”  

• PPPL researcher Sophia Gershman and the New Jersey Institute of Technology (NJIT) are developing innovative low temperature plasma devices for the disinfection and sterilization of surfaces and air from bacteria and viruses such as COVID-19. The project developed a novel technique to produce a device that can treat flat or curved surfaces and reduce the bacteria on a glass surface by 99.99% when in direct contact with the device. Working with Gershman on this project at NJIT have been researcher Gal Haspel and graduate student Maria Belen Harreguy.

• Igor Kaganovich, a PPPL scientist and co-principal investigator of the PCRF, is overseeing a project with the University of Illinois at Urbana-Champaign that studies an obstacle that reduces the effectiveness of laser-like ion beams. Such beams must be neutralized to perform functions that range from inertial confinement fusion to the production of superhot states of matter that are thought to exist in the core of giant planets like Jupiter. At the University of Illinois, graduate student Nakul Nuwal and scientist Deborah Levin are using a code they developed to model the behavior of electrons in plasma, extending previous research at PPPL on a surprising source of reduced neutralization.

• Princeton researcher Arthur Dogariu, a pioneer of advanced optical diagnostic techniques,

conducted a project at the University of Texas at Arlington (UTA) that characterized the high-velocity flow of plasma in an arc jet facility — a wind tunnel-like device that tests the heat-resistance of innovative materials for space vehicles reentry to Earth reentry. Such materials will be vital for crewed Moon or Mars return missions, according to the UTA team. Heading the team is Luca Maddalena with graduate students Daniel Palmquist and Vijay Gopal, together with postdoctoral researcher Davide Vigano. “This work demonstrated that these new optical, non-intrusive techniques can be used to characterize the flows in the arc jet tunnels in a way that was not done before,” Dogariu said.

• Shurik Yatom of PPPL is working with researchers at Washington University in St. Louis  to investigate the interaction of plasma with liquid. The team, led by Elijah Thimsen and graduate student Trey Oldham, is exploring the potential to use plasma for electrochemistry, the branch of chemistry that deals with the relations between electrical and chemical phenomena and has wide-ranging applications. “At PCRF we are particularly interested in applying cutting-edge measurement approaches to characterize the plasma and its interaction with liquids,” Yatom said. The interest in plasma-liquid interactions “has grown exponentially in recent years,” he said, “due to the ability of plasma to decontaminate water and create reactions in water and liquids that benefit medicine, agriculture, and other fields.” 

• Raitses conducts a collaborative project with Kai-Mei Fu of the University of Washington on low temperature magnetized plasma for processing materials such as diamond for quantum information network applications. Raitses also completed a fast-track project on characterization of secondary electron emission properties of selected dielectric insulating materials. ASML Holdings, the world-leading developer and manufacturer of equipment for the semiconductor industry, is collaborative user for this project.  

Response to the second solicitation for 2020, which ended Dec. 11, demonstrates an even greater demand for PCRF state-of-the art capabilities, Raitses said. The facility has received 54 user proposals, including 36 experimental proposals and 18 modeling proposals, covering a broad range of low temperature plasma science and applications. These proposals come from some 50 entities, mainly university researchers, with 10 proposals from industry plus a number from national laboratories.

Support for the PCRF comes from the DOE Office of Science. The facility is managed by PPPL and is open for all collaborators and users.

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.