5
International Aspects of High Energy Density Science

OVERVIEW

This chapter broadly reviews the international high energy density (HED) science landscape, including brief words on collaborations versus competition, the international HED science workforce, and sensitive information.

As a disclaimer, the committee did the best it could in trying to marshal evidence about relative strength of science in different countries. The committee was unable to obtain reliable information on programs in China and Russia, with various claims lacking independent validation. Level of investment, availability of facilities and the like serve, at best, as proxies, and the evidence is mainly anecdotal. Additionally, the committee was not aware of recent developments allowing it to assess theory, modeling, and simulation capabilities internationally.

INTERNATIONAL HIGH ENERGY DENSITY SCIENCE LANDSCAPE

Traditional HED science with high-energy lasers and pulsed-power Z-pinches is still led by the United States. The National Ignition Facility at Lawrence Livermore National Laboratory remains the leader in laser energy at 1.8 MJ, and Sandia National Laboratories’ Z-pinch is the most powerful, operating at currents of 26 MA.

There is only one similar laser facility, the Laser Megajoule (LMJ) facility at the French Alternative Energies and Atomic Energy Commission (CEA). It is currently ramping up to reach a maximum energy of 1.3 MJ by 2025. The LMJ is operational with the current research primarily devoted to France’s nuclear-weapon Stockpile

Stewardship Program (see Box 4-1) and, like NIF, there is some limited academic access through an open call program. LMJ and NIF have active and fruitful collaborations and exchanges on facility, diagnostics, and ICF experiments.

The highest power Z-pinch outside the United States operates at a current of 8 MA and is located at the Julong-1 facilities at the China Academy of Engineering Physics (CAEP).

Although HED science has been traditionally carried out at large experimental facilities with either high-energy lasers or with pulsed power Z-pinches, the growth in Petawatt scale lasers is changing the outlook of HED science. In 2021, using the CoReLS laser, at the Center for Relativistic Laser Science in Gwangju in the Republic of Korea, the highest laser intensity to date was measured at 1.4 × 10²³ W/cm². Light pressure is given by the intensity divided by the speed of light. This intensity then gives a pressure of over 10²⁰ Pa, which is more than 9 orders of magnitude larger than the pressure threshold of 100 GPa for HED science.

With these extreme light pressures, new directions are being discovered for HED science in areas such as new matter and materials created by laser-induced, high-pressure extreme states; shock physics in plasmas; particle acceleration; laboratory astrophysics with giant magnetic fields; and vacuum quantum optics. These high laser intensities can be reached at a greatly reduced energy with ultrafast lasers, which use lower-cost facilities than the traditional high-energy laser ICF facilities (see also Box 5-1).

As noted in the 2018 National Academies of Sciences, Engineering, and Medicine report Opportunities in Intense Ultrafast Lasers: Reaching for the Brightest Light,¹ Asia and Europe now lead in this field, even though the first petawatt lasers were developed in the United States. Figure 5-1 shows the global distribution of high-intensity lasers. Not only does Europe have far more high-intensity lasers than North America, the most powerful lasers are in Europe and Asia. The Korean laser has a power of 4 PW, while in Europe the Extreme Light Infrastructure Nuclear Physics facility demonstrated laser powers of 10 PW in 2020. The United States does not have any lasers at the 10 PW power level, while China is now developing a 100 PW laser system.

Materials science under extreme pressure can now also be studied at small facilities using diamond-anvil technology. The largest effort in this domain is being carried out at a new research center in China, HPSTAR: Center for High Pressure Science and Technology Advanced Research (see Box 5-2). Forefront HED research is more international than ever, overall (see Figure 5-2).

___________________

¹ National Academies of Sciences, Engineering, and Medicine, 2018, Opportunities in Intense Ultrafast Lasers: Reaching for the Brightest Light, Washington, DC: The National Academies Press, https://doi.org/10.17226/24939.

INTERNATIONAL COLLABORATIONS

International collaborations enhance the utilization of HED facilities by offering access to the most diverse and capable workforce. HED facilities are currently mostly utilized by local-national scientists, followed by scientists from the same region of the world.

The main international users of U.S. HED facilities come from Europe; and, likewise, U.S. HED scientists utilize European facilities more than the Asian facilities. Since the highest-intensity laser facility is in Korea, access to that facility should be highly sought, but there does not yet seem to be a good program to bring U.S. researchers to that facility, even though it is open to international scientists and is used by the Europeans.

With the formation of LaserNetUS (see Box 4-6), there is now a channel for international collaborations between laser scientists from Europe, Asia, and North America, so this may improve the level of collaboration with U.S. scientists. Europe and Asia have both established continental networks, LaserLab Europe and the Asian Intense Laser Network (AILN), and already have ongoing collaborations between these two networks.

New international agreements for HED science research, such as the program between U.S. DOE and Japan MEXT in 2019, would aid these collaborations.

International collaborations could also be facilitated through better remote access to the facilities (see Box 5-3). This would help remove the time and expense barriers imposed by travel. Remote access has been increased, especially at the Laboratory for Laser Energetics and other facilities, because of COVID-19 restrictions, and more work needs to be done to improve both the experimental control and the data acquisition for international and domestic remote users at all HED

facilities. In principle, remote access provides a means of controlling access in ways that enhance information security as well as scientific productivity.

INTERNATIONAL WORKFORCE

The United States will need to find ways to attract domestic students and retain international students in relevant domains of science and technology, and to work out solutions allowing those students trained in the United States to remain in the country.

Because much of HED science carried out at large facilities is tied to national needs in the United States as in other countries (e.g., Box 4-1), the workforces at these national facilities come mainly from the home country. The workforce at China’s ICF facility is 100 percent Chinese, for example. To train this workforce, China has graduate level programs in the relevant areas of science and engineering.

Graduate programs within the United States have benefitted from large enrollments of international students. In physics, chemistry, and materials science—areas relevant for HED science—a significant portion of the students receiving PhDs is international: 35 percent in physics, 39 percent in chemistry, and 50 percent in materials science. This level of international student participation also occurs in the university graduate programs held in conjunction with the HED facilities at Stanford University and University of Rochester.

The United States has historically benefited greatly from the immigration of scientists from around the globe. Their skills and perspectives have helped make the United States a historical leader in science and engineering, HED science included. The international character of the U.S. workforce is at risk for a number of reasons, however. First, the number of international graduate students is declining because these students are now experiencing constraints on visas that make it difficult for them to study or work in the United States. Second, competing opportunities in their home country are increasingly attractive.

The rapid growth of HED science as a field having national impact has motivated major investments by several countries, some of which already exceed U.S. capabilities (e.g., in high-intensity lasers). In addition, multiple facilities are planned that significantly exceed U.S. capabilities, in both lasers and pulsed power. This could have a major effect on the U.S. ability to recruit the expert, world-leading workforce needed to maintain a vibrant research capability.

HED science is a collaborative field in nature, and maintaining strong national and international collaborations facilitates retaining and recruiting a global workforce. The growth of HED science offers opportunities for increased collaborations with diverse fields, but it requires a vastly larger network of partnerships and collaborations, both domestically and internationally, as no one institution can

hope to address all the scientific areas of such a vibrant field. Thus, the HED science community should be supported in its active efforts to strengthen and grow partnerships between NNSA laboratories, DOE’s Office of Science laboratories, universities, and industry.

INTERNATIONAL SCHOLARS AND THE IMPORTANCE OF PROTECTING SENSITIVE INFORMATION

International scholars have been major contributors to the research strength of the United States for over a century. As U.S. universities are the envy of the world, international researchers have played a major role in creating that strength. In projects of national security import, such as the Manhattan Project, international contributors from Fermi to Bohr and Bethe played major roles.

The United States has provided, and continues to provide, a welcoming culture for international students and mature researchers—researchers who are committed to pursuing their research in an environment where research integrity is highly valued. These contributors, many of whom have chosen to make the United States home by becoming U.S. citizens, are an integral part of our research strength today. Were the United States to be seen as an unattractive research destination for international researchers, the United States would incur a growing risk of mediocrity and decline.

There are three key reasons why it is essential that the U.S. HED science community strike the proper balance in welcoming international scholars and protecting sensitive information.

• Quality of science. The quality of science in all domains—fundamental, applied, and in service to the nation—is enhanced by broad collaborations because new ideas and creative breakthroughs come from all directions. Thus, wherever possible, encouraging collaborations, including among international researchers, is critical to the health of U.S. science and technology.
• Workforce. Prior to 2020, approximately 80 percent of international students who studied in the United States have wanted to remain here. These

• students have, in many cases, become strong contributors to the science, technology, and engineering advances in the United States. Continuing to attract the best minds from the international community is important for continuing advances in science.
• Maintaining and advancing international understanding and collaborations. Just as the United States maintains informal diplomatic discussions and military-to-military engagements, scientist-to-scientist engagements offer a mechanism for building international understanding, confidence, and insight.

The HED science community is competing for the best minds on a global scale. The good news is that the combination of research environments available in the United States and the structure of U.S. society have been attractive to many international researchers. As other nations are ramping up their research efforts, they too are competing for talent, at times in ways that are antithetical to the norms that characterize research in the United States.

Although the present report is focused on basic research, the committee acknowledges that HED science overlaps with topics having military applications or other sensitivities. Therefore, the committee briefly addresses the interface between sensitive and open research, to emphasize that the relationship between the two must be judiciously managed as progress is made in fields related to HED science. In particular, either ignoring the topic or overly constraining research activities in HED can cause significant harm to scientific progress or to national and international security.

As with all other areas of open scientific research, information needs to be properly managed so as to enhance collaborations and advancement of the science in a manner that is mutually reinforcing, sustainable for all involved, and in line with existing laws and regulations (e.g., the National Science Foundation’s efforts,² and its 2019 Fundamental Research Security report³).

This means that procedures must be in place for making experimental data and results of theory or simulations suitably available among researchers as well as the public at large, and that these procedures are understood and practiced by all participants. Investigators, their institutions, and the user facilities all have responsibilities for ensuring proper access to research results, and any restrictions

___________________

² See National Science Foundation, “Responsible and Ethical Conduct of Research,” https://nsf.gov/od/recr.jsp.

³ See JASON, Fundamental Research Security, JSR-19-2I, McLean, VA: The MITRE Corporation, https://www.nsf.gov/news/special_reports/jasonsecurity/JSR-19-2IFundamentalResearchSecurity_12062019FINAL.pdf.

or special access (e.g., due to licensing agreements) need to be documented, justified, and applied in a transparent manner.

More complex is the issue of export control and related regulations that apply to dual-use research, including the International Traffic in Arms Regulations⁴ (ITAR) and Export Administration Regulations⁵ (EAR) that are largely intended to counter the proliferation of military technologies.⁶ Hardware, software, and either general concepts or the specific results of a study can all be subject to restrictions, and the limitations may vary depending on an individual’s nationality. In other words, a student from one country may be allowed to use a certain computer code, whereas a student of different nationality might not have access to that software, even if working in the same research group. Specific examples include hydrodynamic simulations used for designing HED experiments, which may have restricted access.

It is up to investigators and their institutions to be familiar with these regulations, not only so as to comply with existing laws but also to avoid overly restrictive constraints being placed on scientific research or collaborations. The concern is that inattention by one researcher or institution could prompt the imposition of onerous new restrictions affecting the entire research community—restrictions that would not have been necessary had existing regulations been followed.

More serious, and in some ways more straightforward, is the management of classified information. Here the problem is that unclassified experiments, simulations, or theories and models can in principle produce classified results. Perversely, the silence of the classified community in areas that are well understood by the scientific community risks calling undue attention to sensitive areas. Worse, given the international character of HED science, what is considered unclassified can differ from one country to another.

In the mid-1990s, the Secretary of Energy commissioned a fundamental classification review. The report of the DOE Report of the Fundamental Classification Policy Review Group (1997) recognized the problems inherent in the “born classified” concept of the Atomic Energy Act of 1954 and recommended changes to the act. In addition, the review recognized that domains that had become of interest to the wider scientific community could be sensitive or classified. While the sweeping changes recommended by this review committee have not been implemented, in the past few years, there have been changes to the classification guidance for both

___________________

⁴ See Department of State, “Directorate of Defense Trade Controls,” https://www.pmddtc.state.gov/ddtc_public.

⁵ See Bureau of Industry and Security, Department of Commerce, “Export Administration Regulations,” https://www.bis.doc.gov/index.php/regulations/export-administration-regulations-ear.

⁶ “Dual use” generally refers to research that can have harmful as well as beneficial applications, and in the present context can be taken as referring to research that can be used for military applications or terrorism.

equation-of-state and opacity that are fostering better exchanges between those working in the classified and unclassified communities.

Recognizing the delicacy of research that lies on the boundaries of classification, the primary mitigation for these difficulties at the present time is for facilities and the funding agencies, and—if possible—the investigators and their institutions, to (1) have safeguards for recognizing when prospective research might generate such sensitive information and (2) establish means of mitigating these circumstances. The committee does not elaborate on the best solutions to these issues, but rather emphasizes the need for addressing them within research programs, institutions, and facilities supporting HED science.

Ensuring the health of the research enterprise while simultaneously protecting sensitive information requires a deft touch that engages the research culture, information systems, and researchers.

Information Processing System Security

The current framework is appropriate. As with all U.S. institutions, both universities and national laboratories are bound by existing laws and regulations. Examples include ITAR and classification rules. These are not unlike regulations such as Health Insurance Portability and Accountability Act and Family Educational Rights and Privacy Act in other domains. Given the dynamic nature of information security in cyber space, one can anticipate evolution in the legal and regulatory domain. Similarly, just as U.S. institutions are assumed compliant today, one can anticipate that they will continue to be compliant under current regulations and laws in the future.

Vetting of Foreign National Researchers

The government, universities, and national laboratories have a shared interest in ensuring research integrity through the values of openness and transparency, accountability and honesty, impartiality and objectivity, respect, freedom of inquiry, reciprocity, and merit-based competition—as outlined in the National Science Foundation “Dear Colleague” letter NSF 19-200⁷ and the National Science and Technology Council’s “Recommended Practices for Strengthening the Security and Integrity of America’s Science and Technology Research Enterprise.”⁸

___________________

⁷ National Science Foundation (NSF), 2019, “Dear Colleague Letter: Research Protection,” NSF 19-200, July 11, https://www.nsf.gov/pubs/2019/nsf19200/research_protection.jsp.

⁸ Executive Office of the President, 2021, “Recommended Practices for Strengthening the Security and Integrity of America’s Science and Technology Research Enterprise,” product of the Subcommittee on Research Security, Joint Committee on the Research Environment, National Science and Technology Council, January, https://trumpwhitehouse.archives.gov/wp-content/uploads/2021/01/NSTC-Research-Security-Best-Practices-Jan2021.pdf.

While most researchers both in the United States and abroad share these values, not all do. To ensure the integrity of research, it is important to confirm that researchers are not obviously compromised, either through conflict of interest or conflict of commitment. Research institutions are expected to instill the values of research integrity into all researchers, both from the United States and internationally; specifically, these values need to be defined, communicated, and confirmed in all activities.

In addition, because students and researchers may have been exposed to other value systems, research institutions are expected to exercise due diligence when it comes to the engagement of all researchers. While prudent precautions are necessary, it is also clear that no security measures will guarantee that incidents of concern will not occur; they will. When they do, they must be addressed in balanced ways that forward the simultaneous goals of ensuring the health of the HED science research enterprise and protecting sensitive information.