This month, the National Academies launched a sweeping assessment of recent progress in plasma science and promising avenues for research in the coming ten years. Referred to as “Plasma 2020,” the decadal survey will also address subjects such as how the discipline contributes to economic and national security and whether the current structure of U.S. research programs is appropriate.
At its kickoff meeting on Oct. 15, the study committee discussed ways to capture the breadth of the discipline and how to handle the subfield of nuclear fusion, which has been a focus of congressional debate and is the subject of a separate forthcoming National Academies study.
The “Big Red Ball” at the University of Wisconsin–Madison is a three-meter confinement vessel used to study the behavior of magnetized plasmas. The National Science Foundation funded its construction through a Major Research Instrumentation grant. In 2017, the Department of Energy allocated funds to convert its host laboratory into a user facility, granting external researchers access to the ball and a separate device called the Madison Symmetric Torus.
(Image credit – Jeff Miller / UW–Madison)
The study of plasma, a state of matter that consists of unbound charged particles, spans a wide array of scientific disciplines. For instance, as plasma is the substance comprising stars and most visible interstellar matter, it is of central interest in astrophysics and space weather research. It also has a range of established and prospective practical applications, from the etching of microelectronic circuits to the generation of electrical power through nuclear fusion.
The variety of federal agencies sponsoring Plasma 2020 reflects the breadth of the field. They include the Department of Energy, National Science Foundation, Office of Naval Research, and Air Force Office of Scientific Research. Within DOE, the Office of Science, National Nuclear Security Administration, and Advanced Research Projects Agency–Energy are helping to support the study. At NSF, four divisions are contributing funds.
Slava Lukin, program director for plasma physics at NSF, described the agency’s cross-cutting support for the discipline and outlined its priorities for the survey. They include articulating major scientific questions in the field, identifying opportunities for universities to contribute to the national research effort, and assessing workforce demographics and needs. Lukin also urged committee members to set aside their disciplinary preferences and present an integrated picture of the field.
“It’s the job of this decadal to bring the community together,” he said.
In the DOE Office of Science, the Fusion Energy Sciences (FES) program is the primary stakeholder in plasma science. The office’s High Energy Physics program also has a significant interest in the field because of the potential for plasma wakefields to serve as an acceleration method for next-generation particle collider facilities.
Although the bulk of the budget for FES is dedicated to magnetic confinement fusion (MCF) research, FES also supports “discovery” science that is not directly connected to the goal of generating energy from fusion. This part of the research portfolio spans topics such as plasma astrophysics, high energy density laboratory plasmas, and low-temperature plasmas.
Acting FES Director Jim Van Dam told the committee he would like Plasma 2020 to identify ways FES could strengthen its core program as well as pursue new research thrusts, citing quantum information science, machine learning, laser facility upgrades, materials testing, and microelectronics as areas of particular interest.
Tom Mehlhorn, head of the Plasma Physics Division at the Naval Research Laboratory, described how the division’s portfolio spans almost every branch of the discipline except for magnetic fusion energy research. He said about a third of the portfolio focuses on space plasmas, motivated in part by the Navy’s reliance on space-based navigation systems during remote deployments.
He also noted the division receives about 40 percent of its budget from NNSA. As part of its nuclear weapons stockpile stewardship program, NNSA supports inertial confinement fusion (ICF) research at several major laser facilities, the largest being the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory.
Mehlhorn identified ICF as being among the topics the Navy would like the Plasma 2020 committee to consider. He said that although a NIF program manager had “poisoned the well” for ICF by overselling the prospects for achieving fusion ignition, it remains a critical research area despite current talk of “fusion fatigue.”
FES is currently awaiting the recommendations of a separate National Academies study committee that is assessing its MCF research activities. That committee issued an interim report last year and is expected to release its final report in December. The Plasma 2020 committee has been directed not to alter its recommendations or those from the latest decadal survey for solar and space physics.
A topic that looms large over FES is participation in ITER, a massive international MCF facility under construction in France for which the U.S. has pledged to cover one-eleventh of the costs. Senate appropriators have repeatedly proposed to zero out its budget following a period of management turmoil at the facility, while their House counterparts have successfully fought to keep money flowing to it.
With this as the backdrop, the Plasma 2020 committee discussed to what extent it should broach the topic of fusion. One member noted the committee could sidestep the subject altogether to avoid contradicting the other report, but also pointed out that the outlook for ITER could have significant implications for the rest of the FES portfolio.
Van Dam acknowledged that ITER had squeezed other portions of the FES budget in the past, but said Congress has since protected the domestic research program. He also said confidence in ITER’s management has improved and he believes there is a greater appreciation of the project’s value in the current administration.
“I’m hopeful that this is not necessarily a zero-sum game,” he concluded.
The discussion returned to fusion during a session with Emily Domenech and Adam Rosenberg, the majority and minority staff directors of the House Science Committee’s Energy Subcommittee. They described how some of the most significant provisions in the recently enacted DOE Research and Innovation Act pertain to FES, including a directive for the secretary of energy to produce a ten-year strategic plan for fusion energy R&D.
Rosenberg said that in recent years DOE has been unable to produce a fusion energy strategy that has sufficient support from the research community despite several attempts. The staffers also sought to allay concerns raised by some committee members that Congress might conflate other branches of plasma science with fusion research.
“Most of the argument on Capitol Hill is about fusion-based plasma work because that’s where most of the money goes,” Domenech said, adding that the lack of discussion of other plasma science research areas is an indication they are uncontroversial. She said the Plasma 2020 report could help drive increased investments in plasma science at agencies, but also acknowledged that problems in the fusion part of the portfolio could be an impediment to launching a major interagency initiative.
The meeting participants also discussed the impact of the previous decadal survey , released in 2007. Referred to as Plasma 2010, its principal recommendation was for the DOE Office of Science to adopt a “stewardship role” for the entire discipline.
Van Dam recounted that in response to that recommendation, DOE took steps to increase support for discovery plasma science. He cited the creation of a low-temperature plasma research center at the University of Michigan and a mid-scale plasma science user facility at the University of Wisconsin–Madison as examples.
In contrast, Lukin said Plasma 2010 had “pretty much no impact” on NSF because it did not identify a “unique leadership role” for the agency. Nevertheless, he said NSF has increased its support for plasma science over the past decade by funding several mid-sized experimental facilities at universities, forming a new partnership with NASA, and strengthening the longstanding NSF-DOE Partnership in Basic Plasma Science and Engineering . He noted NSF recently hosted a workshop commemorating the 20th anniversary of the NSF-DOE partnership, the formation of which was a primary outcome of the first decadal survey for the field, published in 1995.
Steven Cowley, who co-chaired Plasma 2010, explained the rationale behind the report’s recommendations in a presentation to the committee. Cowley, who now directs the Princeton Plasma Physics Laboratory, said the Plasma 2010 panel felt the NSF-DOE partnership program had leveled out at a funding amount they thought was insufficient and they wanted an agency to take responsibility for ensuring the field remains healthy.
“I’m not sure we did the right thing, but what we decided was that the one place that this was vital to the mission of the agency was within DOE,” he recounted. “I think that the Office of Fusion Energy Sciences has worked hard to try and provide some stewardship for plasma science in the last ten years.”
Speaking to the overall impact of Plasma 2010, Cowley said he believes it contributed to a “groundswell that moved things organically.”
“Not one report causes anything actually,” he later added. “It has to be the community.”
