Plasma Science: Advancing Knowledge in the National Interest (2007)

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E Reprise of Past NRC Reports on Plasma Science Since 1994 the National Research Council (NRC) has produced five reports examining various aspects of plasma science: the last decadal study, Plasma Science: From Fundamental Research to Technological Applications (1995). Database Needs for Modeling and Simulation of Plasma Processing (1996), An Assessment of the De- partment of Energy’s Office of Fusion Energy Sciences Program (2000), Frontiers in High Energy Density Physics: The X-Games of Contemporary Science (2003), Burning Plasma: Bringing a Star to Earth (2004), and Plasma Physics of the Local Cosmos (2004). In this appendix, the committee considers the impact of these reports and the response to their report recommendations. To emphasize the historical nature of the issues discussed in this report, the committee also comments on the NRC report Plasmas and Fluids (1986). In the 1995 study Plasma Science: From Fundamental Research to Technological Applications, it was recognized that support for basic plasma science had dropped to a perilously low level. More than half of the report’s principal recommendations dealt with this issue. Key facets of these recommendations were as follows: • Emphasis should be placed on university-scale research programs. • The National Science Foundation should provide increased support for basic plasma science. • The Department of Energy Office of Basic Energy Sciences, with the co- operation of the Office of Fusion Energy Sciences (OFES), should provide increased support for basic experimental plasma science. • Approximately $15 million per year for university-scale experiments should 243 

244 Plasma Science be provided and continued in future years to effectively redress the current lack of support for fundamental plasma science. • The allocation of funds between larger, focused research programs and individual-investigator and small-group activities should be reassessed. • The agencies supporting plasma science should cooperate to coordinate plasma science policy and funding. • The plasma community should work aggressively for recognition of plasma science as an academic discipline eligible for tenure. Partly in response to recommendations made in the 1995 report, the joint NSF/DOE Partnership in Basic Plasma Science and Engineering in was created in 1997. Proposals for basic laboratory plasma research have been solicited triennially. The matter of which programs at an agency participate in the solicitation generally depends on the subject matter of the proposals submitted. At NSF, the divisions of physics, astronomy, atmospheric sciences, and several programs in engineering have been involved; at DOE, only the OFES has been involved. The joint NSF/DOE program currently operates at a funding level of approximately $6 million per year (see Appendix D for more description). This program has become an important funding source for basic plasma research in the last decade; it is responsible for much of the research progress described in this chapter. In parallel, OFES created a General Science Program to fund basic research at DOE laboratories and a very successful Young Investigator Program to fund research by junior faculty at colleges and universities. Extending the legacy cooperation in supporting laboratory plasma science, DOE and NSF recently supported the creation of the Physics Frontier Center for Magnetic Self-Organization in Laboratory and Astrophysics Plasmas, a center of excellence based jointly at the University of Wisconsin and the Princ- eton Plasma Physics Laboratory and involving six other institutions at the level of several million dollars per year. Programs such as these have had a strong positive influence on basic plasma science and increased connections between the fusion program and the broader scientific community. During the same period (1995-2006), a vital and effective program for basic plasma research at the Office of Naval Research at the level of $4 million per year was terminated owing to changing U.S. Navy priorities. In some ways, however, emerging programmatic support at DOE’s NNSA (e.g., the Stockpile Stewardship Academic Alliance program) has helped offset this loss by providing stewardship for the growing area of laboratory explorations of HED plasmas. The NSF/DOE Partnership in Basic Plasma Science and Engineering has been effective in terms of important research progress as measured, for example, by publication in Physical Review Letters. It has also contributed greatly to the pro- duction of new scientific and technical personnel for the field as measured by the production of Ph.D.’s in plasma science. It has made important connections with other areas of science and has achieved greater recognition of plasma science by 

A pp e n d i x E 245 the broader scientific community. The program has been a very effective vehicle in providing support for the research being done by tenure-track faculty. The success of this program is limited by the relatively small funding base and a triennial funding cycle in which unfunded proposals must generally wait 3 more years for reconsideration. In the latest round of solicitations, only 20 percent of the proposals were funded, with the average grant size being $100,000 per year. The 1995 report also had some specific comments about low-temperature plasma science. Many positive science and technology trends foreseen at that time have in fact been realized: • Cathodes and sheaths are the subject of collaborative efforts around the world. • A U.S. research consortium investigated the sources of infrared radiation (waste energy) from high-intensity discharge lamps. • The use of plasmas for air and water treatment continues to grow. • Plasma propulsion has grown enormously, well beyond the expectations of the 1995 report. Other predictions and trends have been more ambiguous: • Large-scale computation, though having had considerable impact, has not had as wide a role as anticipated, nor have methods to tailor models of the electron-energy distribution for higher efficiency. • The historical importance of gas lasers, isotope separation, and magneto- hydrodynamics to the field was highlighted, but there were few predictions about the future. In fact, there has been little research in these fields outside the classified work by the national laboratory communities. The conclusions and recommendations of the 1995 report are still quite relevant: • “Research in low-temperature plasma has decreased substantially, primarily because the largest source of funding, the federal government, has had a shrinking budget for such activities in the last several years.” There are few agencies or programs today within the U.S. government to which proposals for basic low-temperature science can be submitted, virtually the only one being the relatively modest NSF/DOE Partnership. This program awards a few millions of dollars every 3 years. During the last solicitation, only a  NRC, Plasma Science: From Fundamental Research to Technological Applications, Washington, D.C.: National Academy Press, 1995, pp. 1-3. 

246 Plasma Science few funded projects addressed low-temperature plasmas of technological interest. • “Research has also been adversely affected by the recent recession and a general move of large U.S. companies to divest themselves of manufac- turing.” This trend continues today. Only the highest-value research and manufacturing are not being moved offshore. • “The panel recommends that one agency within the government be given the responsibility for coordinating research in low-temperature plasma science.” Today, no U.S. government agency is charged with stewardship of low-temperature plasma science and engineering. In the spring of 1994, the Plasma Science Committee and the Committee on Atomic, Molecular, and Optical Sciences of the NRC established a panel to organize and conduct a workshop on database needs in plasma processing of materials. The report of that workshop was published in 1996 as Database Needs for Modeling and Simulation of Plasma Processing. The primary purpose of the workshop was to bring together experts to develop a prioritized list of database and diagnostic needs based on their potential impact on plasma-processing science and technol- ogy. At the time, plasmas in one form or other were used in about 30 percent of all semiconductor manufacturing processing steps, and about the same fraction of processing equipment is plasma-based in a typical microelectronics fabrication facility. An important trend accompanying this growth in the industry is the fact that the capital cost of constructing a new microelectronics fabrication facility is similarly escalating and is now on the order of $1 billion or more. Estimates are that as much as 60 percent of this capital cost has been for processing equipment, including plasma equipment. The report contains a host of findings, conclusions, and recommendations. Little specific progress at the federal level has occurred, although recent interagency discussions on database needs have resumed. In part, the report found that federal funding agencies should make greater and more systematic efforts to support de- velopment of an improved database for plasma modeling and that a spectrum of plasma models should be developed for a variety of uses. The committee also rec- ommended that at least one data center should be established to archive, evaluate, and disseminate the existing and future database for models of plasma materials processing in integrated circuit manufacturing. The 2000 report An Assessment of the Department of Energy’s Office of Fusion Energy Sciences Program considered the effectiveness of the OFES science program. The key recommendations of this report are these: • Achieving scientific understanding should be a recognized goal of the program. 

A pp e n d i x E 247 • The scientific isolation of the field should be reduced. • New fusion science centers should be created at universities. • The fusion community should develop the case for and support a burning plasma experiment. • The NSF should expand its role in sponsoring general and fusion plasma science. • Fusion energy and fusion energy science should be reviewed periodically by an external panel. The report also recognized the growing predictive capability in fusion science. The response to this report was good but not complete—indeed, the commit- tee revisits some of the same issues in this report. The establishment by OFES of two fusion science centers and the funding of the NSF Physics Frontier Center at Wisconsin have greatly increased connections to universities and reduced scientific isolation. As is discussed in greater detail below, the case for a burning plasma experiment was developed by the fusion community and articulated effectively in the 2004 report Burning Plasma: Bringing a Star to Earth. The mechanism for reviewing (and planning) the future strategy of the OFES program is still an issue of concern. In Frontiers in High Energy Density Physics: The X-Games of Contemporary Science, the emerging trends in HED physics were examined. The key recommen- dations were these: • Increase access to NNSA facilities by external users interested in basic HED physics. • Increase NNSA and other agency funding of HED research at universities. • Maximize the ability of facilities to explore fundamental HED science. • Support university-scale HED science. • Improve the integration of computational and experimental results. • Strengthen interagency cooperation to foster basic HED science. The response to these recommendations has been promising. The interagency working group that was assembled charged a task force with identifying the key components of a national HED science program. While the elements have indeed been identified, the goal of providing some structure and coordination for the field has yet to be realized. In any event, the key issues in HED science are revisited and updated in the present report. The Burning Plasma Assessment Committee (BPAC) was charged with as- sessing the importance of a burning plasma experiment, the readiness to perform such an experiment, DOE’s plan for such an experiment, and the best strategy for making progress toward fusion energy. BPAC reported first in a letter that urged 

248 Plasma Science the U.S. government to rejoin ITER, the international burning plasma experiment. The key recommendations of the report Burning Plasma: Bringing a Star to Earth are these: • The United States should participate in a burning plasma experiment; if possible, this should be ITER. • The U.S. fusion program should be strategically balanced, which will re- quire an augmentation of funding beyond ITER construction funds. • The U.S. fusion program should make a focused effort to recruit and train a new generation of fusion scientists for the burning plasma era. • The fusion program should undertake a prioritization process, recognizing that in order to expand burning plasma research, some facilities will have to be shut down over time and that hard choices must be made. The response to the report has been mixed. The United States is proceeding as a partner in ITER, and plans for the U.S. role in ITER are being formulated. However, there is still no plan that outlines how facilities will evolve up to and including ITER. The strategic balancing issues identified in the Burning Plasma report are discussed in the final section of Chapter 4 of this report. Plasma Physics of the Local Cosmos (2004) provides a detailed description of the scientific challenges in space plasma science. Specific recommendations are contained in the parent volume Sun to the Earth—and Beyond: Panel Reports. However, these are outside the scope of the present report. The 1986 study Physics Through the 1990s: Plasmas and Fluids was the first NRC decadal survey of physics to explicitly include plasma science. The panel was cochaired by Ronald Davidson and John Dawson and included four separate subpanels whose membership extended beyond that of the main panel. The report identified promising research opportunities in plasma physics and made general recommendations in addition to many subfield-specific comments. Of particular note, the committee made two overarching recommendations: • Because fundamental understanding of plasma properties precedes the discovery of new applications, and because basic plasma research can be expected to lead to exciting new discoveries, increased support for basic research in plasma physics is strongly recommended. • The impact of plasma physics on related sciences and technology has con- tinued to grow since the birth of modern plasma physics in the late 1950s and will continue to grow for the foreseeable future, provided a strong research base for plasma physics is maintained.