The fields of fusion energy research and plasma science and engineering were described in Chapter 1, along with the scientific and technological opportunities they present. In this chapter, we present recommendations on how the Department of Energy (DOE) Fusion Energy Sciences (FES) research program should capitalize on those opportunities. Acting on the recommendations below would create a research and development (R&D) program that would move aggressively toward practical fusion energy, deepen our understanding of plasma science, and create transformative plasma technologies. Realization of the strategic plan, including enabling the progress needed to confidently prepare for a fusion pilot plant (FPP) by the 2040s, will require timely implementation of all of these recommendations.

This requires substantial additional resources to be added to the program compared to the FY19 budget. The recommendations are grouped into two categories. Overarching Recommendations are independent of specific programs or facilities and viewed as essential to successful execution of the DOE FES research program. Project and Program Specific Recommendations are grouped into three subcategories: Fusion Science and Technology Program, Plasma Science and Technology Program, and Cross-cutting that apply to all programs. The order of presentation of these recommendations does not imply priority; all recommendations should be acted on to fully realize the strategic plan. Prioritization of activities is expressed through the budget scenario descriptions below.

Overarching Recommendations

The Community Planning Process (CPP), completed early in 2020, resulted in the fusion and plasma science research communities coming to consensus on new directions for FES-funded research. This first recommendation aligns the strategic plan with the consensus view, as summarized in Chapter 1:

• Recommendation: Align the program with the six technology and science drivers in order to establish the scientific and technical basis for a fusion pilot plant by the 2040s and advance fundamental understanding of plasmas that translates into applications that benefit society.

Experimental research and technology development in fusion energy and plasma science require state-of-the-art facilities, often at large scale. US participation in the international ITER experiment is critical to accessing burning plasmas at reactor scale. The US has invested significantly over the past decade in the design and construction of ITER and will continue to do so over the coming decade to ensure access. However, additional high-priority research gaps will require the development of large-scale facilities to be successfully addressed. Outside the important investment in ITER, there has been little investment over the past decade in the development of major new experimental capabilities. Addressing the technology and science drivers will require continuing investment in the design, construction and operation of facilities that provide important new capabilities. Such investment is necessary to maintain a vigorous scientific program and to achieve necessary breakthroughs in numerous areas. This strategic plan provides a framework for sequencing the development of those new capabilities.

• Recommendation: Resources for ongoing design and construction of major new experimental facilities should be established in the DOE FES budget.

Although large-scale facilities are essential to make progress in many areas, important aspects of the technology and science drivers can be successfully addressed through the development of small and medium-scale experimental facilities. Such facilities are amenable to siting at universities, where investments can have high impact, provide leadership opportunities to faculty and junior scientists, and help develop the workforce needed to execute this strategic plan.

• Recommendation: Opportunities should be provided for developing new experimental capabilities at a range of scales, as appropriate to address the goals of this strategic plan.

The strategic plan should be regularly updated to adapt to new scientific discoveries, technological breakthroughs and other changes in the R&D landscape.

• Recommendation: This long-range planning process, including a strong community-led component, should be repeated no later than every five years in order to update the strategic plan.

Strategic planning is most effective if ideas for major new experimental capabilities are developed to the preconceptual stage, preferably with mission need and scope well defined and a preliminary cost range established. The Critical Decision process within DOE provides a framework for accomplishing this goal, and utilizing this process to routinely refine the design of needed new experimental facilities is highly desirable.

• Recommendation: Maturation of preconceptual designs, scope, and costing for proposed new experimental facilities should be part of regular program activities.

Fusion and plasma science research has strong and growing commercial connections to US industry. These connections exist across the whole portfolio of industry applications, and an opportunity exists for DOE to take a more active role in translating advances stemming from federally funded research into commercial applications. Public–private partnerships (PPPs) should be formed with private industry and used as a paradigm for accelerating fusion and plasma science research to benefit both the government-funded program and private companies. Research conducted in the private sector can benefit from federally supported programs by offering more cost-effective pathways to retire risk in key gap areas while establishing the industrial infrastructure critical for the next steps in fusion energy and plasma technology. Access to public facilities and programs can be leveraged to solve technical problems by private companies that do not have the public sector’s capabilities. Public–private partnership should be used as a tool to stimulate industry involvement. DOE FES has already established successful PPP programs, notably the Innovation Network for Fusion Energy (INFUSE). These activities should be expanded, and new PPP programs, including milestone-based cost-share programs, should be developed. Investment in PPP activities should align with priorities in the strategic plan and be balanced by robust investment in federally funded programs to maximize effectiveness of the partnership. Further discussion of specific opportunities in PPP is offered in Appendix B.

• Recommendation: Expand existing and establish new public–private partnership programs to leverage capabilities, reduce cost, and accelerate the commercialization of fusion power and plasma technologies.

Research and development in fusion energy and plasma science and technology is inherently interdisciplinary. Given the broad range of applications where these fields have relevance, there is also a range of federal agencies that currently provide research support, including the Air Force Office of Sponsored Research, DOE ARPA-E, DOE Advanced Scientific Computing Research, DOE High Energy Physics, DOE National Nuclear Security Administration, NASA, the National Science Foundation (NSF) and the Office of Naval Research. Coordination among these federal programs has led to extremely successful research programs; the NSF–DOE Partnership in Basic Plasma Science and Engineering and the Joint Program in High Energy Density Laboratory Plasmas with the NNSA and FES are prominent examples. Expanding on those successes and increasing program coordination, including cooperative construction and support of experimental facilities, could make better use of federal resources and enable more rapid progress toward development of fusion energy and advancement of plasma science and engineering.

• Recommendation: Explore and implement mechanisms for formal coordination between funding agencies that support fusion and plasma science research.

Successfully addressing the challenges of bringing fusion power to the grid and advancing the frontier of plasma science requires innovation, creativity, and a talented, multidisciplinary and diverse workforce. Barriers to assembling this workforce should be addressed in order to achieve the goals in this strategic plan.

First, the fusion and plasma community is not accessing the available talent pool in our current workforce. Data show that our research community has significant deficiencies in workforce diversity, with participation from women and underrepresented minorities below national averages for other subfields of physics and engineering. This is not just an issue of recruiting talent, but also of retaining talent, something that is affected by the culture within the community and that could be addressed through embracing equity and inclusion.

Second, DOE lacks the tools necessary to direct development of the needed workforce to execute this strategic plan. The Office of Management and Budget recently implemented a policy change that significantly limits workforce and outreach programs at DOE. The new policy was intended to reduce duplication of education and outreach activities at federal agencies, but it had the unintended consequence of eliminating discipline-specific outreach and workforce programs that were not being duplicated at other agencies.

Below we offer overarching recommendations on diversity, equity, inclusion, and workforce development. We dedicate Appendix C to more specific recommendations.

• Recommendation: DOE and FES should develop and implement plans to increase diversity, equity, and inclusion (DEI) in our community. Done in consultation with DEI experts and in collaboration with other institutions, this should involve the study of workplace climate, policies, and practices, via assessment metrics and standard practices.
• Recommendation: Restore DOE’s ability to execute discipline-specific workforce development programs that can help recruit diverse new talent to FES-supported fields of research.

Program and Project Specific Recommendations

The following recommendations address specific elements of the Fusion Science and Technology (FST) and Plasma Science and Technology (PST) program components. As with the earlier recommendations, resource priorities across and within program components are delineated in the budget scenarios, which follow this section, and not by recommendation ordering.

Fusion Science and Technology

The recommendations described below are aimed at realizing the overall goal of establishing the technical basis for an FPP by the 2040s. It is therefore implicit that all recommendations are implemented in time to be consistent with achieving that goal.

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The underlying theme guiding the strategic plan is the need to move aggressively toward the deployment of fusion energy. The design, construction, and operation of a fusion pilot plant (FPP) is recognized as a critical milestone toward that goal. The coordinated program delineated here develops FPP concepts that can advance to engineering designs and rapidly adapt to innovations and advances in understanding. Physics modeling efforts also must be brought together with engineering tools in order to address issues beyond the fusion core, including balance of plant equipment, licensing, remote handling, maintenance, and reliability. Cutting-edge physics, materials and engineering, and integrated models need to be applied to viable confinement concepts and operating scenarios so as to continuously inform research needs and priorities. Both the public and private sectors have a diverse range of stakeholders for an FPP, and they will all need to participate in such a coordinated effort.

• Recommendation: Initiate a design effort that engages all stakeholders to estab lish the technical basis for closing critical gaps for a fusion pilot plant, utilizing and strengthening the world-leading US theory and computation capabilities and engineering design tools.

Construction of a viable FPP will require significant technology development beyond the burning plasma itself. Critical enabling technologies such as plasmafacing components, structural and functional materials, and breeding-blanket and tritium-handling systems are not yet advanced enough for an FPP. The time required to develop these technologies at present levels of support is incompatible with the goal of a fusion pilot plant by the 2040s. Increased support for these program areas is therefore critical, as is an increased emphasis on foundational fusion materials and technology research. That emphasis includes the expansion of theory and modeling work that supports advancing technology readiness levels (TRLs), accelerating development of diagnostics and measurement systems that will function in fusion nuclear (irradiation-hardened) environments, and rapidly maturing enabling technologies. This includes the expansion of theory and modeling efforts that support advancing technology readiness levels, such as the development of validated models at a range of complexities suitable for inclusion in integrated modeling capabilities needed to accelerate the development and qualification of new materials.

• Recommendation: Rapidly expand the R&D effort in fusion materials and technology.

Fusion nuclear facilities including an FPP will require new materials to be conceived, developed, and qualified for nuclear use. This process is well understood for nuclear components having a clear path that includes laboratory development, standardized testing, and regulatory oversight and approval. While mixed spectrum fission reactors are and will remain the primary workhorse for R&D and for obtaining qualification-level data of irradiated materials, they do not produce the appropriate spectrum for materials irradiated in a fusion reactor core. In this region, the fusion-born neutrons will produce significant, yet largely unknown, effects on structural and nonstructural components of the first wall, divertor, and blanket. To develop materials that withstand high levels of fusion neutron irradiation and can be qualified for FPP service, an irradiation facility that can produce the required damage and transmutation rates is necessary. The Fusion Prototypical Neutron Source (FPNS) recommended here should be highly reliable and have the flexibility to increase the damage rate. The primary utility of this facility will be to translate the measured effects of the fusion spectrum and transmutation products into codes with predictive capability. Toward that end a comprehensive program of modeling, advanced characterization, and high-temperature nuclear-structural design criteria is necessary. These tools, along with the construction of an FPNS, will build upon the US leadership in fusion materials technology.

• Recommendation: Immediately establish the mission need for an  FPNS facility to support development of new materials suitable for use in the fusion nuclear environment and pursue design and construction as soon as possible.

Physics-based understanding of plasma-material interactions (PMI), including the development of predictive capabilities for the material response and exhaust solution, is necessary to construct and qualify plasma-facing components (PFCs) for an FPP. Reaching these capabilities will require support for the completion of the scientific infrastructure, of which the Material Plasma Exposure eXperiment (MPEX) is a central piece. MPEX is a linear plasma exposure device that will be uniquely equipped to access prototypical plasma conditions in a fusion reactor divertor. The MPEX is currently in the design-to-build process. Additionally, high-heat-flux testing via a coupon-level (centimeter-scale samples) facility early and a component-level (tens of centimeters to 1 meter scale) facility later will allow for development of materials and qualification of components for an FPP. Together with the existing PMI facilities, these world-leading capabilities will allow for validation of PMI models that will form the base of PFC design tools for an FPP.

• Recommendation: Develop the scientific infrastructure necessary for the study of  plasma-materials interactions needed to develop plasma facing components for an FPP by completing the MPEX and additional high-heat flux testing facilities.

Closure of the fusion fuel cycle via successful breeding and extraction of tritium will be critical for the sustained operation of an FPP. However, breeding-blanket technologies are presently at a low technology readiness level and are unlikely to advance to this demonstration stage without significantly increased R&D support. In the near term, this should entail a variety of separate effect test stands and subcomponent fission reactor irradiations to understand fundamental tritium transport properties and phenomena in solid and liquid breeder materials, as well as associated modeling and model validation efforts. Tritium technologies related to fueling and exhaust from the plasma, and subsequent processing, will be demonstrated at significant scale in ITER. The program should involve tritium experts in the US ITER team so as to maximally benefit from this technology demonstration. It should also support additional R&D of technologies necessary to significantly reduce the size, cost, and tritium inventory of a plant based on ITER technologies. Since there is no current path for the US to deploy a test blanket module in ITER, this program should also develop a strategy for componentscale blanket testing in a nuclear environment and support preconceptual design and costing studies for facilities such as a blanket component test facility (BCTF), fission irradiations (e.g., HFIR, ATR), fusion irradiations (e.g., FPNS), and volumetric neutron source (VNS), that accomplish both missions on a time scale necessary to enable the FPP.

• Recommendation: Significantly expand blanket and tritium R&D programs.

To confidently design a low-capital-cost tokamak FPP, several gaps in tokamak physics understanding need to be closed. These include advancing understanding of transport and stability physics for sustaining disruption-free, high-averagepower-output operation; energetic particle and burning plasma physics relevant to a high-fusion-gain FPP; and plasma-material interactions and material choices for exhaust solutions. Critical issues must also be addressed to integrate improved understanding into operational scenarios for an FPP. Important issues in tokamak physics can be addressed immediately through a comprehensive, multidisciplinary science program utilizing the world-leading DIII-D and NSTX-U facilities alongside important smaller-scale facilities at universities. Particular areas of emphasis on DIII-D include resolving the disruption and transients challenge and informing long-pulse steady-state operation. Areas of emphasis for NSTX-U include low aspect ratio physics, PMI control, and liquid metal PFC evaluations. A broader set of opportunities on DIII-D and NSTX-U to close key gaps in a timely fashion should be pursued when doing so proves cost effective and accelerates progress toward an FPP. The success of ITER and other future highcurrent tokamaks assumes that the disruption and runaway electron prevention/ avoidance/mitigation techniques developed on existing machines translate to practical solutions for those future devices. If such solutions cannot be developed, then a stronger focus on advanced tokamak or spherical tokamak approaches that utilize lower current, higher beta, and/or higher bootstrap fractions and which have been shown to be less disruptive than high-current scenarios will be required, as well as more vigorous pursuit of alternate confinement concepts including optimized stellarators. Collaborations on planned public and private domestic and international facilities, particularly those that focus on long-pulse conditions inaccessible in the US, will provide unique contributions to advance tokamak physics in these areas.

• Recommendation: Utilize research operations on DIII-D and NSTX-U, and collaborate with other world-leading facilities, to ensure that FPP design gaps are addressed in a timely manner.

In addition, the US should fully exploit its participation in ITER to gain experience with a burning plasma and fusion technology while benefiting from the shared cost through an international partnership. ITER is the baseline path to a reactorscale burning plasma and provides unique technology advances that will accelerate the FPP development path. To ensure timely involvement by the prefusion-power operation phase starting in 2028, the US urgently needs to establish a framework for developing an appropriate workforce. This should be centrally organized, with participation in system design and commissioning efforts in the near term and activities ramping up as the project moves toward first plasma. Other near-term opportunities include integrated modeling for scenario development of the first operational phases and establishing data standards. Once operations begin, there should be a particular emphasis on further advancement and qualification of disruption prevention, avoidance, and mitigation solutions in preparation for final demonstration in ITER DT plasmas; significant US R&D could support this area.

• Recommendation: Ensure full engagement of the  US fusion community in ITER by forming an ITER research team that capitalizes on our investment to access a high-gain burning plasma.

Even with existing and planned facilities, it will not be possible to address all outstanding physics issues needed for the US vision of a tokamak-based FPP, followed by an economically attractive power plant. In particular, this vision requires demonstrating integrated strategies for handling exhaust heat fluxes well beyond what is expected in existing or planned devices, while simultaneously supporting sustained high core plasma performance. Specifically, these solutions must be demonstrated to be compatible with FPP-relevant disruption prevention, avoidance and mitigation solutions developed using current domestic tokamaks, collaborations, and ITER operation. A range of options for closing this Integrated Tokamak Exhaust and Performance (ITEP) gap were considered, including upgrades to existing facilities and collaborations on both private and international tokamaks. While those options provide opportunities to partially bridge this gap, none were judged sufficient to address the fundamental core-edge integration challenge encapsulated by the ITEP gap. Closing that gap is necessary to ensure FPP readiness. Building upon the recommendations of the NASEM Burning Plasma report, we recommend the construction of a new domestic tokamak, named EXCITE (EXhaust and Confinement Integration Tokamak Experiment), as the optimal solution for closing the ITEP gap. The envisioned EXCITE design would offer a unique combination of flexible power exhaust capabilities, plasmafacing component options, control actuators, and access to plasma conditions that would enable continued US leadership in tokamak physics into the 2030s. At the same time, EXCITE is envisioned as a modestly sized high-field device utilizing short-pulse, non-nuclear operation to enable design and construction on an acceptable time scale at manageable cost. This approach requires an immediate, significant design and costing effort to advance solutions to the ITEP gap and confirm the EXCITE mission and scope. The activity should make full use of world-leading US integrated modeling capabilities to develop preconceptual designs for EXCITE. The designs will be utilized in a detailed assessment of cost and technical feasibility and compared to alternative gap-closure approaches such as enhanced collaborations and upgrades. The design effort should include participation from private industry and international groups to accelerate the EXCITE schedule and reduce costs.

• Recommendation: Immediately establish the mission need for an  EXCITE facility to close the integrated tokamak and exhaust gap and aggressively pursue design and construction.

A tokamak with solid plasma-facing components is currently the primary path to commercial fusion. Four innovative areas aimed at addressing key vulnerabilities of this approach will potentially lead to more economically attractive commercial fusion power systems while leveraging areas of US leadership.

• Stellarators offer intrinsically disruption-free operation with low recirculating power. The optimized quasi-symmetric stellarator concept is a unique US design approach that is complemented by international collaboration at the W7-X and LHD stellarators. A new domestic midscale US stellarator experiment should be realized.
• Liquid metal plasma-facing components potentially expand the reactor-wall power limits and alleviate lifetime constraints due to material erosion. Low-recycling, liquid lithium walls may open up pathways to high plasma confinement and compact FPP designs. Development of liquid metal plasma-facing-component concepts in non-plasma test stands and existing magnetic confinement facilities should be targeted and should build on PFC concepts developed in the existing domestic program.
• Inertial fusion energy (IFE) utilizes advances in lasers, pulsed power technology, and other innovative drivers to achieve fusion at high fuel density. The enormous progress made with indirect drive at the National Ignition Facility, direct drive, magnetic drive inertial confinement fusion (ICF), and heavy ion fusion underpin the promise of IFE. An IFE program that leverages US leadership and current investments should be targeted.
• Breakthroughs in alternate magnetic-confinement concepts, beyond tokamaks and stellarators, could lead to a lower-cost FPP and subsequently more economically attractive fusion power. Examples of such concepts include those that require no plasma current; have moderate or zero toroidal magnetic field; and are compact, pulsed plasma targets that may eliminate auxiliary heating. A program that supports innovative magnetic fusion energy concepts should be considered.
• Recommendation: Strengthen the innovative and transformative research program elements that offer promising future opportunities for fusion energy commercialization: stellarators, liquid metal plasma-facing components, IFE, and alternate concepts.

Plasma Science and Technology

Fundamental plasma science explores new regimes and deepens our understanding of nature. It includes theories that propose foundational descriptions of plasmas and their nonlinear, multiscale, collective behavior; computational methods required to predict outcomes of those theories; and experiments that test theoretical predictions and validate models. The knowledge these discoveries provide makes possible the innovative plasma-based technologies that will advance the field. The future of plasma science will rely on consistent support through contiguous grant cycles, even when spending fluctuates for construction projects and large program elements.

• Recommendation: Provide steady support for fundamental plasma science to enable a stream of innovative ideas and talent development that will lay the scientific foundation upon which the next generation of plasma-based technologies can be built.

Advances in energy compression with intense lasers and pulsed-power facilities have made it possible to squeeze matter to extreme pressures, creating exotic dense plasma states similar to those thought to exist in the interiors of giant planets and stars. However, our ability to diagnose or probe the structure and dynamics of these high-energy-density (HED) plasmas is inherently difficult due to the very dense and rapidly evolving conditions. Transformational measurement techniques are necessary to develop a physics-based understanding to pursue some of the grand challenges in HED physics, including, for example, warm dense matter (WDM) material properties, relativistic laser-plasma interactions, magnetic field generation, and plasma particle acceleration. X-ray free electron lasers can give such sensitive measurements of HED plasma states that they provide an atom’s eye view with attosecond precision and significantly advance the state-of-the-art. Not only is MEC-Upgrade the central piece needed to achieve these HED science goals, it can also lead to breakthroughs in our understanding of materials needed for fusion.

• Recommendation: Complete the design and construction of  MEC-Upgrade.

Technologies derived from plasma science investments have had a transformative effect on modern society. The translation of discoveries in low-temperature plasmas, for example, has created the semiconductor manufacturing industry, which provides advanced personal electronics. Plasma-based technologies will continue to improve quality of life with advances in environmental-hazard clean up in air, soil, and drinking water; advanced methods for medical treatment and imaging; and electronics. Plasma-based chemical processing has the potential to revolutionize industry by enabling the production of new materials and an innovative means to recycle plastics and other wastes. It will address climate change by greatly improving the efficiency of typically energy-intensive chemical processes and by offering ways to convert carbon-free electrical energy into the products that power society. Translation of basic plasma science research into actual technologies can be accelerated by a more organized and formal investment, including partnerships with industry and other federal agencies—for example, NSF, the National Institutes of Health (NIH), the Department of Agriculture, and the Environmental Protection Agency.

• Recommendation: Establish a plasma-based technology research program focused on translating fundamental scientific findings into societally beneficial applications.

High-intensity lasers are opening new fields across plasma physics, from highenergy-density science and laboratory astrophysics to new diagnostics and particle sources for science and industry. Two recent reports, NASEM’s Opportunities in Intense Ultrafast Lasers: Reaching for the Brightest Light, and the 2019 Brightest Light Initiative Workshop Report, enumerate the reasons to invest in intense ultrafast lasers. A new organization should be developed to maintain the vitality of this research field in the US and to make available the necessary petawatt-scale and high-repetition-rate laser technologies. FES could lead in coordinating a high-intensity-laser research initiative to support needs in discovery science and advance energy technologies. This would resolve fragmentation where no single national funding agency has responsibility for the field as a whole. Agencies making investments in this area include DOE FES, DOE High Energy Physics (HEP), DOE Accelerator R&D and Production (ARD&P), DOE NNSA, the NSF, and DOD.

• Recommendation: Coordinate a High-Intensity-Laser Research Initiative in collaboration with relevant DOE offices and other federal agencies.

Advanced lasers that go beyond the state of the art in high peak power and in very high average power (kilowatts and beyond) would open new frontiers in the laser-based science of particle acceleration, advanced light sources, high-field physics, nonlinear quantum electrodynamics, laser-driven nuclear physics, laboratory astrophysics and exotic materials. Competition in this arena is fierce, with scores of multi-petawatt lasers planned in Europe and Asia and petawattclass high-repetition-rate laser facilities already in operation internationally. However, the US has an opportunity to stay competitive by leveraging decadeslong investments and know-how in laser technology, while combining competencies in multiple emerging technologies—machine learning, advanced manufacturing, diagnostics, and edge computing—to develop a formidable capability that will rapidly accelerate the HED field.

• Recommendation: Pursue the development of a multi-petawatt laser facility and a high-repetition-rate high-intensity laser facility in the US, in partnership with other federal agencies where possible.

Networks provide an organizational structure that supports collaboration by increasing access to experimental facilities, diagnostics, and computational tools. LaserNetUS is an existing, very successful program that partially supports facility maintenance and operation, coordinates users, and evaluates proposals. The program allows researchers that otherwise lack access to state-of-the-art facilities to conduct frontier experiments; it would enable workforce development and facilitate coordination and collaboration. This or a similar model would likely have a comparable impact in other areas of plasma science and technology, including in low-temperature plasmas, laboratory-magnetized plasmas, and pulsed power. In addition to access to experimental facilities and user support, networks should include access to resources for computational modeling and diagnostics. Networks are also a mechanism to organize the community input that defines next-generation user facilities.

• Recommendation: Support networks to coordinate research and broaden access  to state-of-the-art facilities, diagnostics, and computational tools.

Space and astrophysical plasma physics are enjoying an exciting time of discovery, as advances in spacecraft missions and remote observations provide insights into previously inaccessible regions in the solar system and beyond. The Parker Solar Probe spacecraft is orbiting close enough to the Sun to directly measure the solar wind at its origin. The mechanisms by which the solar wind is accelerated and heated are among the most persistent and important open research topics in plasma science. Recent advances in deep space imaging have culminated in the first visualization of an accretion disk—the turbulent, rotating plasma that is generated as material is gravitationally pulled toward a black hole. Understanding these phenomena presents a timely opportunity for FES to establish a new laboratory-based space and astrophysical plasma program. Controlled laboratory experiments, for example, can isolate, control, and diagnose plasma phenomena responsible for the complex behaviors seen in plasma systems throughout the cosmos. A partnership could be established with NASA in a focused laboratory space/astro plasma physics program, taking advantage of a recent NASA–DOE memorandum of understanding affirming mutual interest in collaborative activities pertaining to energy-related civil space activities. The existing partnership between DOE and NSF could also be leveraged for such an activity, including collaboration on needed facilities in this area. There is a need within the community to advance the capabilities of experiments, and to develop a solar-wind-relevant midscale experiment, to better compliment the advances in spacecraft technology and observation. Laboratory experiments can be a crucial intermediate between observation and computer simulation. In particular, they can provide specific conditions and environments that can be modeled in great detail in simulation frameworks.

• Recommendation: Strengthen support of laboratory-based research relevant to astrophysical and space plasmas through increased programmatic and facility funding as well as expansion of partnership opportunities.

Cross-cutting Recommendations

To successfully carry out this plan, foundational research activities that reach across the breadth of the FES portfolio must be robustly and continuously supported. Fundamental theoretical research, separate from computation, remains essential for developing new models, insights, and innovations in topics across plasma and fusion science and technology. Foundational theory work also enables the FES community to continue to take advantage of and expand advanced scientific computing and the tools that can further improve our fundamental understanding and predictive modeling capabilities, including new methods in machine learning (ML), artificial intelligence (AI), and quantum information science (QIS). This work is also essential for fusion and plasma research to take full advantage of US investments in exascale computing. All of these investments in theory and computation are vital to the continued development of variously complex validated models, including integrated modeling capabilities, an area in which, historically, the US has shown strength and leadership. A continued close partnership between FES and the Advanced Scientific Computing Research (ASCR) program is therefore essential to realizing these opportunities and to sustaining investment in computational user facilities and capacity computing resources. A healthy program for developing diagnostics, measurement, and control techniques for a reactor environment, and the broader environment of plasmas is needed to support progress toward an FPP and toward deeper understanding of plasma science. Community consensus favors increased support for programs to develop critical enabling technologies that advance plasma and fusion science and technology and reduce the cost of resulting applications, including an FPP. In each of these cross-cutting areas, the CPP report identified a wealth of needs and opportunities that should be addressed and pursued.

• Recommendation: Ensure robust support for foundational research activities that underpin all aspects of plasma and fusion science and technology.

Models and diagnostics in many areas of plasma science rely heavily on fundamental data for physical processes such as cross sections and rate coefficients and for materials properties such as strength and opacity. These essential elements of plasma physics and nuclear science should be more strongly supported. In many instances, models are limited by the absence of accurate input data rather than by a lack of knowledge of plasma physics. Research that both supplies and verifies such fundamental data is essential to advance in many areas of plasma science, including development of models. That type of research does not currently have a clear source of funding.

• Recommendation: Support research that supplies the fundamental data required to advance fusion energy and plasma science and engineering.

Budget Scenarios

Prioritization of projects and research programs is expressed through addressing the constant level of effort, modest growth, and unconstrained (but prioritized) budget scenarios as described in the charge. It should be emphasized that no additional recommendations are made in addressing the budget scenarios. Measures taken to address the constrained scenarios do not represent additional stand-alone recommendations outside the very specific budget scenario being addressed. While the constrained scenarios require difficult choices, they represent a balanced program with prioritization and emphasis on critical elements that advance the fusion energy mission and sustain scientific impact and technological progress. Importantly, the implementation of activities described in the constrained scenarios allows for continued growth should more favorable budgets develop in the future. Nonetheless, the constrained scenarios do not provide sufficient resources to confidently prepare for FPP construction by the 2040s, and large projects in the plasma science and technology area are unfunded. That lack of funding has consequences: It will cost the US its position as a global leader in fusion energy and plasma science and will compromise future developments with important societal implications. Therefore, we do not recommend either of the two constrained scenarios—namely, the constant level of effort or modest growth—and point to the substantial return on investment that comes with pursuing programs and facilities enumerated in the unconstrained but prioritized scenario.

In all three scenarios, there is a conscious decision to direct resources to the activities identified by the community as the most essential and urgent to enable construction of an FPP. That decision includes a strategic pivoting toward R&D in fusion materials and technology (FM&T). The pivot is necessary because FM&T R&D is on the critical path to an FPP, independent of the eventual choice of FPP plasma core(s). The strategic plan in all scenarios emphasizes innovation in both physics and technology as a means of establishing a unique leadership opportunity for the US fusion and plasma community, and recommends corresponding programs be supported in parallel with facility developments. Following the charge, the scenarios start from the FY 2019 budget and specifically focus on the non-ITER construction project portion. The FY 2019 budget did not include significant resources dedicated to design and construction of facilities. For that reason, in the two constrained scenarios below, any recommended new construction is funded by redirecting resources from current facility operations and research programs. This redirection is consistent with the consensus view of the research community, as expressed in the CPP report:

“The community recognizes that designing and constructing major new facilities may not be possible without progressively redirecting resources from existing facilities. Given the possibility of constrained budgets, there is significant support among the community to pivot resources from existing facilities to fund new programs and facilities, if necessary, so that new facilities can be operational within ten years or less. The resources and research programs of existing facilities should immediately evolve to reflect the priorities of this plan. Any such transition must be mindful of the workforce needs and impacts associated with diverting operations budgets to construction.”

In addressing the scenarios, redirection is confined within each of the two thematic areas (FST and PST). The PST portion of the FY 2019 enacted budget is relatively small, and redirecting it, even in its entirety, would be insufficient to support yearly costs for proposed major facility construction. As a result, under the two constrained budget scenarios, major facility construction in the PST area is not possible. Importantly, that shortfall results in not completing the ongoing MECUpgrade project in the two constrained budget exercises. This project is headed toward Critical Decision 1 during FY 2021 and, notably, has received line-item status in the congressional budget, with significant resources allocated to the project in FY 2020 and in FY 2021. The message to be taken from the budget scenarios below is that new resources are required to support design, construction, and operation of the critically important MEC-Upgrade facility, and that message is consistent with actions already taken by Congress to support this project in FY 2020 and FY 2021. Table 1 (see page 42) summarizes program and facility actions for each scenario.