Department of Energy | December 2015

Executive Summary
The vision described here builds on the present U.S. activities in fusion plasma and materials
science relevant to the energy goal and extends plasma science at the frontier of discovery.
The plan is founded on recommendations made by the National Academies, a number of recent
studies by the Fusion Energy Sciences Advisory Committee (FESAC), and the Administration’sviews on the greatest opportunities for U.S. scientific leadership.
This report highlights five areas of critical importance for the U.S. fusion energy sciences
enterprise over the next decade:1) Massively parallel computing with the goal of validated whole-fusion-device
modeling will enable a transformation in predictive power, which is required tominimize risk in future fusion energy development steps.
2) Materials science as it relates to plasma and fusion sciences will provide thescientific foundations for greatly improved plasma confinement and heat exhaust.
3) Research in the prediction and control of transient events that can be deleterious totoroidal fusion plasma confinement will provide greater confidence in machine
designs and operation with stable plasmas.
4) Continued stewardship of discovery in plasma science that is not expressly driven by
the energy goal will address frontier science issues underpinning great mysteries ofthe visible universe and help attract and retain a new generation of plasma/fusion
science leaders.
5) FES user facilities will be kept world-leading through robust operations support andregular upgrades.
Finally, we will continue leveraging resources among agencies and institutions andstrengthening our partnerships with international research facilities.

Fusion Energy Science Program: A Ten-Year Perspective | Page iDepartment of Energy | December 2015

THE OFFICE OF SCIENCEFUSION ENERGY SCIENCE PROGRAM:A TEN-YEAR PERSPECTIVE
Table of Contents
Legislative Language ................................................................................................................... 1
1. Progress in Fusion Energy Sciences ................................................................................. 3
1.1: The Promise and Scientific Character of Fusion Energy Sciences Research 3
1.2: Leading Frontiers in Fusion and Plasma Science ........................................ 8
2. Community Input .................................................................................................................. 10
2.1: Recent FESAC Assessment of Program Priorities ..................................... 10
2.2: Community Workshops in 2015 ............................................................... 11
2.3: Previous Community Studies ................................................................... 12
3. Research Directions ............................................................................................................. 15
3.1: Burning Plasma Science: Foundations...................................................... 15
3.2: Burning Plasma Science: Long Pulse ........................................................ 18
3.3: Burning Plasma Science: High Power ....................................................... 21
3.4: Discovery Plasma Science ........................................................................ 23
4. Funding Scenarios ................................................................................................................ 26
4.1: Modest Growth Scenario ......................................................................... 26
4.2: Cost-of-Living Budget Growth Scenario ................................................... 27
4.3: Flat Funding Scenario .............................................................................. 28

Fusion Energy Science Program: A Ten-Year Perspective | Page ii

Department of Energy | December 2015

Legislative Language
This report responds to legislative language set forth in the Explanatory Statement
accompanying the Consolidated Appropriations Act, 2014, for a strategic plan for fusion energy
sciences research in the United States:“Not later than 12 months after enactment of this Act, the Department shall submit aten-year strategic fusion plan to the Committees on Appropriations of the House ofRepresentatives and the Senate. The ten-year plan should assume U.S. participation in
ITER and assess priorities for the domestic fusion program based on three funding
scenarios with the fiscal year 2014 enacted level as the funding baseline: (1) modest
growth, (2) budget growth based only on a cost-of-living adjusted fiscal year 2014
budget, and (3) flat funding. The January 2013 Nuclear Science Advisory Committee
report on priorities for nuclear physics used similar funding scenarios and should serve asa model for assessing priorities for the fusion program.”
In that same Congressional report was a request for a plan for implementing a validated,predictive, integrated simulation program for fusion energy sciences:“Not later than 180 days after enactment of this Act, the Department shall submit to theCommittees on Appropriations of the House of Representatives and the Senate a planwith research goals and resource needs to implement a Fusion Simulation program.”
Further, this report responds to the request expressed in the Explanatory Statement
accompanying the Consolidated and Further Continuing Appropriations Act, 2015:“The Office of Science is further directed to seek community engagement on thestrategic planning and priorities report through a series of scientific workshops on
research topics that would benefit from a review of recent progress, would havepotential for broadening connections between the fusion energy sciences portfolio andrelated fields, and would identify scientific research opportunities. The Department isdirected to submit to the Committees on Appropriations of the House of Representatives
and the Senate not later than 180 days after enactment of this Act a report on its
community engagement efforts.”
In addition, this report covers the Department’s response to the following legacy reporting
requirements):•••

Energy and Water Development Appropriations Bill, 2009, House Report 110-921, page
115
Fiscal Year 2012 Conference Report to accompany H.R. 2055, page 855); House Report112-118, page 113; Senate Report 112-75, page 94
Energy and Water Development Appropriations Bill, 2014, Senate Report 113-47, page
95
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Department of Energy | December 2015•

Energy and Water Development Appropriations Bill, 2014, House Report 113-135, page109

Fusion Energy Science Program: A Ten-Year Perspective | Page 2

Department of Energy | December 2015

1. Progress in Fusion Energy Sciences
1.1: The Promise and Scientific Character of Fusion Energy
Sciences Research
The frontiers of fusion science exist at the extremes of the plasma state, the state of matter ofwhich stars and well over 99 percent of the visible universe are composed. These extremes
range from very small to extremely large, from very slow to very fast, from diffuse to extremely
dense, and from ultra-cold to ultra-hot. The Fusion Energy Sciences program supports researchextending from end to end of each of these ranges, challenging our ability to produce andmeasure matter at the extremes.
In addition to these experimental and diagnostic challenges, numerically simulating such
systems requires the development of sophisticated modeling tools and use of advanced
computing platforms based on fundamental theoretical understanding.
The scientific knowledge necessary to create fusion energy under controlled conditions iscentered on the study of plasmas and their interactions with the materials that enclose them.
Plasmas—the fourth state of matter—are gases hot enough that electrons have been knocked
free of atomic nuclei, forming an ensemble of ions and electrons that can conduct electricalcurrents and respond to electric and magnetic fields. Stars, lightning bolts, flames, and halogen
lighting consist of plasma. Inside the Sun, tremendous gravitational forces create plasmapressures high enough that hydrogen nuclei frequently collide and fuse into new atomic nuclei.
The end products following the fusion event actually weigh less than the original colliding
nuclei; some of the mass is converted into tremendous energy of motion of the fusion products
according to Einstein’s famous formula, E = mc2. With the Sun, it is this energy released fromthe fusion process that becomes the radiant energy that warms the Earth.
Successful development of fusion energy science and technology in the laboratory would leadto a base-load power source for developed and emerging economies, with a fuel supply that isabundant. Since the earliest experiments conducted over 60 years ago, the pursuit of fusionenergy has been a challenging program of research and development. Establishing a deep
scientific understanding of the requirements for harnessing and optimizing this process on
Earth is critical, and is the driving force behind the Department of Energy’s (DOE) programmaticinvestments in this area. The progress to date warrants major new steps in critical areas so as
to further advance fusion’s scientific and technical viability. This document describes what isrequired for the U.S. to take those steps.
The scientific progress has been tremendous, and fusion’s remaining research frontiers are
replete with questions of the highest scientific order. Although producing prodigious amountsof energy is the ultimate goal, over the years research progress in fusion has broadened anddeepened scientific knowledge in numerous areas with broader impact, such as self-organizedFusion Energy Science Program: A Ten-Year Perspective | Page 3

Department of Energy | December 2015
system complexity, non-linear turbulent energy transport processes, magnetohydrodynamics,
energy exchange between dynamic magnetic fields and particles, energy exchange between
plasma waves and energetic particles, and the interactions between materials and theunimaginably harsh environment of a fusion plasma. In addition, studies of fusion,
astrophysics, and industrial plasma applications have benefited from significant synergy,
yielding, for example, the ability to confidently study in the laboratory phenomena relevant toexotic astrophysical processes as well as to perform precise manipulation of plasmas forindustrial applications. Indeed, many of the mysteries of the visible universe present scientificchallenges in the realm of plasma physics, fusion’s original scientific discipline.
All of these achievements have been enabled by, and have themselves promoted, first-of-a-kindcapabilities in massively parallel computing and innovations in detailed measurement of theplasma state. The National Energy Research Scientific Computing Center (NERSC), one of thepremier supercomputing centers in the U.S. today, was originally called the Controlled
Thermonuclear Fusion Computing Center when it was founded in 1974 and was dedicated tosimulations of the behavior of plasma in fusion reactors. Its name was subsequently changed
to National Magnetic Fusion Energy Computer Center (MFECC) and then to NERSC as its mission
was expanded beyond fusion to provide supercomputing services to all of the Office of Science
program offices. NERSC was the first unclassified supercomputer center and became the modelfor others that followed.
Historically the United States has been a global leader in fusion energy research. In the years
after World War II, scientists, buoyed by the rapid progress in nuclear physics and thesuccessful Manhattan Project efforts to control fission processes, were optimistic that practicalfusion energy would follow quickly. However, fusion proved to be more challenging than
anticipated, largely due to the difficulty in achieving and controlling the extreme physicalconditions required to sustain fusion reactions. These form the basis of the scientific research
program pursued today by DOE and others worldwide.
The vision of a working fusion energy reactor is as follows: Fusion fuel atoms (usually a mixtureof the hydrogen isotopes deuterium and tritium) will be ionized to form the plasma state andfurther heated to extremely high temperatures on the order of 100 million degrees, where thenuclei fuse. Some of the fusion energy released will be shared with the plasma itself, and theplasma will self-heat, promoting more fusion reactions. Energy released in fusion reactions andcarried by energetic ions and neutrons will then be captured and converted into heat, which isused to drive conventional power plant equipment to put useable electric power on the grid.
Today, fusion reactions are created and controlled in research laboratories. Leading
experiments have generated megawatts of fusion power for seconds at a time. While rich inscientific value, experiments to date have had a negative energy balance: in other words, moreenergy has been required to create the fusion reactions than has been released. Experimental
efforts are now on the verge of realizing the long-sought goal of creating fusion reactions withnet energy gain, an achievement that would enable a new era of science and that would
provide the platform for a demonstration power plant. What is missing is an experimental
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Department of Energy | December 2015
effort of appropriate scale that will generate the self-heated plasma state so as to test andadvance the knowledge base required for being able to control it in an attractive manner, toextract energy from that plasma, and to generate the fuel in a closed cycle from the fusion
reactions themselves.
There are two different technological approaches to fusion energy: magnetic-confinement
fusion energy (MFE) and inertial-confinement fusion energy (IFE). It is the science of MFE thatis predominantly supported by FES, because this is the approach that has shown the mostprogress in realizing the conditions required for high power and sustained operation. In MFE,
carefully arranged magnetic fields are used to physically confine plasma inside a vacuum vessel,
where it is isolated in a controlled environment. To create the conditions for fusion to occur,
the plasma is heated with energetic particle beams and radio-frequency waves tothermonuclear temperatures. Fusion fuel can then be introduced into the plasma to initiate
the reaction. To sustain the fusion reaction process and keep the fusion fuel at thermonuclear
temperatures, the plasma must be contained and effectively insulated from the comparatively
cool walls of the confining vessel.
Keeping the plasma confined and well-behaved under the extreme conditions required forfusion reactions is challenging, but progress has been dramatic. Indeed, while larger and morecapable fusion devices were being constructed during the past three decades that took
advantage of increases in scientific understanding, the performance for magnetic-confinement
fusion research has increased by a factor of 100,000 (where performance is measured by the
triple product of plasma density, plasma temperature, and energy confinement time). In
particular, deuterium-tritium experiments conducted in the 1990’s on the Tokamak Fusion Test
Reactor (TFTR) at the Princeton Plasma Physics Laboratory in the U.S. and on the Joint
European Torus in the U.K. achieved a central fusion power density that met reactor
requirements, and plasma self-heating from energy released in the fusion process wasobserved. Progress in understanding the dynamical behavior of plasmas and how to control it
has been equally dramatic.
Fusion energy sciences research routinely involves the synergy of experiments, theory,computational science, and diagnostic development. The U.S. has been a world leader inestablishing this synergistic scientific foundation. Examples include the following:•

Fusion-grade plasmas that match the extraordinary conditions of fuel temperature
required in a fusion reactor are now routinely created in U.S. laboratory experiments.
The understanding developed from these experiments is enabling optimization of fusion
plasma conditions for ITER and other future burning plasma experiments.

•

Fine details determining the heat confinement of the fusing plasma state, including
temperatures of hundreds of millions of degrees centigrade and fuel fluctuation levels
smaller than 0.1 percent of the average fuel density, are routinely measured with
precision. Rapid analysis of such measurements is now used by scientists in real time toguide the generation of successive plasma pulses during experiments.
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Department of Energy | December 2015•

Fusion scientists have made significant contributions to the fields of turbulence,complex dynamics, and self-organization, subjects that are important not only forfusion, but also many other scientific endeavors, such as climate research.
Computational and measurement advances regarding plasma turbulence have led to arevolution in the understanding of fusion system containment properties and the likely
characteristics of future experiments, including ITER.

•

Scientists are able to exert exquisite control of plasmas for fusion research as well asother applications. This control includes active feedback between real-timemeasurements and heating and magnetic field actuators that react within milliseconds
to the early detection of potentially deleterious instabilities, allowing their targeted
suppression before fusion plasma performance is degraded.

•

Precisely configured magnetic fields safely direct enormous heat fluxes (many millions
of watts per square meter) from fusion plasmas onto material structures that aredesigned to endure this harsh environment.

•

Fusion researchers led the nation indeveloping the first supercomputing
applications supported by DOE.
Nowadays, at DOE-sponsored national
supercomputer centers, U.S. researchers
carry out numerical simulations that
continue to push the state of thecomputational art. Present-day codes
capture the complex details of fusion
plasma, and its interactions with thematerials that surround it.

•

From the SciDAC Center for Edge Physics Simulation

Fusion scientists have been among the
A visualization of the fluctuations of electrostatic
potential perturbation, obtained from a petascaleleaders in materials science, identifying
numerical simulation of ion-temperature-gradientmaterials that can endure the many
turbulence in a realistic global DIII-D geometry.
atomic displacements that will occur inan eventual fusion reactor, andunderstanding their properties with theoretical and computational analyses.

The science of high energy density laboratory plasmas (HEDLP) underlies the inertial fusionenergy (IFE) approach, in which the fuel is rapidly compressed under enormous pressure toreach fusion conditions and then the inertia of the fuel keeps it together long enough for fusion
to occur. HEDLP research is supported by FES and is important for understanding not only thefusion process but also astrophysical systems. Laboratory experiments and sophisticatedsimulations are used to investigate the physics of stellar interiors as well as their atmospheres
Fusion Energy Science Program: A Ten-Year Perspective | Page 6

Department of Energy | December 2015
and, in another regime, to understand and control low-temperature plasmas for industrial
applications as well as for the sake of unraveling their fundamental physics.
Research accomplishments in plasma astrophysics are many and include the following:•

Laboratory experiments and numericalsimulations are being used tounderstand the generation of solar
prominences and the formation ofplasma jets that extend hundreds oreven thousands of light years from agalactic core.

•

Understanding the mystery of thesurprisingly high temperature of thesolar corona – over 1,000,000 kelvinmeasured 10,000 km above the Sun’sphotosphere, while the Sun’s photosurface resides at a comparatively cool
4,500 kelvin – has benefited from major
discoveries in laboratory experiments.
These confirm that the process ofmagnetic reconnection can efficiently
convert the energy of the Sun’s tangled
magnetic field into thermal energy ofsolar corona ions. Theory andexperiment also indicate that thisenergy can be efficiently transported tothe outer reaches of the corona via
plasma waves.

Solar flare, photo courtesy of NASA

Research on the formation of solar flares and intergalactic
jets is supported by FES in a partnership with the National
Science Foundation.

Credit: NASA, ESA, S. Baum, C. O'Dea, R. Perley, W. Cotton,•

Plasma environments that simulate the
Hubble Heritage Team (https://science.nrao.edu/facilities/vla)
conditions on the surfaces of white
A combined radio and optical image of Hercules A. The
dwarf stars that eventually become
galaxy is the patch in the center; the radio jets, driven by
Type IA supernova have been generated
plasma processes, extend far beyond.
in the laboratory, providing a platformto perform detailed assessments of the
intrinsic brightness of these stars.
Astronomers use Type-IA supernova as “standard candles” to evaluate intergalactic
distances. This research may improve the accuracy of our best “cosmic yardsticks,”
allowing a precise determination of the age of the universe.

•

Fundamental principles of plasma physics have been applied to measurements obtained
by Voyager 1 and 2 missions of the solar wind near Pluto to set the internationally
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Department of Energy | December 2015
accepted upper bound on the mass of the photon at nearly 10-51 grams, a dramatic
improvement over previous such estimates.
•

Computer codes used to understand fusion plasmas are being applied to theextraordinary conditions in the accretion disks of black holes, including research tounderstand the apparent deficit in luminosity of the accretion disk surrounding themassive black hole at the center of the Milky Way galaxy.

These research examples highlight the reach of fusion and plasma science and only scratch thesurface of what has been accomplished. The great drive now is to extend the intellectual
framework of the fusion sciences into the next essential frontier, that of burning plasma
science.

1.2: Leading Frontiers in Fusion and Plasma Science
Today there are several frontiers in fusion and plasma science. The global magnetic fusion
research community is focused primarily on the commencement of the “burning plasma” era.
While many of the essentials of burning plasma science are mature, some critical pieces remain
unexplored and will remain so until experimentation at the necessary scale and capability isundertaken. ITER is the vehicle for gaining access to these critical pieces, including the physics
of the self-heated burning plasma state, which opens up a new frontier in science and also will
enable questions critical to advancing fusion energy to be engaged and ultimately answered.
Burning plasma is fundamentally different from plasmas that have been created in researchfacilities to date. It is essential to create and study burning plasma in order to advance fusionenergy, because it is only in burning plasma that the issues of energy confinement, heating, andstability are fully coupled, along with nuclear science issues. The importance of moving into
this era was affirmed in a 2004 National Academy of Sciences review, Burning Plasmas –Bringing a Star to Earth. 1 This report recognized that a burning plasma experiment is essential
to assessing the scientific and technical feasibility of fusion as an energy source. Its strongest
recommendation was that the U.S. fusion science research program should pursue the rich andimportant scientific questions that will only be accessible by the creation of burning plasma in
the laboratory.
A second great scientific challenge for fusion is to develop materials that can tolerate theextreme conditions created by burning plasma in a fusion reactor. Plasma at a high enoughtemperature and density to undergo nuclear fusion in a reactor generates close to a billion
watts of fusion power. This presents a uniquely hostile environment to the materials of thereactor, both due to enormous heat fluxes—tens of millions of watts per square meter
impinging on a wall—and to a harsh shower of neutrons that will displace their constituent

1

http://www.nap.edu/catalog/10816/burning-plasma-bringing-a-star-to-earth

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Department of Energy | December 2015
atoms and thus qualitatively change their material strength and other characteristics. There isa clear opportunity for the U.S. to seize international leadership in the broad area of materialscience relevant to fusion energy systems and technologies over the next decade. A 2007
FESAC report identified a broad range of fusion materials research needs. This knowledge gap
must be filled if ITER is to be a penultimate step to a demonstration fusion reactor.
A third broad frontier is termed “discovery plasma science”—the fundamental study of a wide
variety of plasma systems. This field is not only fundamental to facilitating the production andcontrol of fusion energy, but also to understanding the nature of visible matter throughout thecosmos. Additionally, discoveries in plasma science are leading to an ever-increasing array ofpractical applications, ranging from energy-efficient lighting, to low-heat, chemical-freesterilization processes. The ability to create and manipulate plasmas with densities andtemperatures spanning many orders of magnitude has led to the establishment of plasma
science as a multi-disciplinary field, which is necessary for understanding the flow of energy andmomentum in the universe as well as enabling the development of various breakthroughtechnologies.
The ten-year vision for the FES program presented in this report would promote U.S. scientificleadership in each of these three areas. We anticipate continuing to work closely with thefusion and plasma science research community to refine the vision on an evolving basis.

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Department of Energy | December 2015

2. Community Input
This report is based on a variety of types of input from the scientific community, including a
number of important recent studies, which are described below. Further evolution of the vision
will be informed by continual engagement with the community, most immediately through aseries of “research needs” community workshops scheduled for mid-2015.

2.1: Recent FESAC Assessment of Program Priorities
In April 2014, in response to the congressional reporting requirement, the Acting Director of the
Office of Science charged the Fusion Energy Sciences Advisory Committee (FESAC) to provide areport prioritizing elements of the FES program within explicit budget constraints. The resulting
report, Report on Strategic Planning: Priorities Assessment and Budget Scenarios 2 (hereafterreferred to as FESAC 2014), emphasized four primary research thrusts that are rooted in a
number of highly regarded community studies (cf. Section 2.3).
The Office of Science supports the four primary research thrusts of FESAC 2014 and groups
them together equally rather than prioritizing them into two tiers.

2•

Control of deleterious transient events: The category of transient events refers to rapid
plasma instabilities (specifically, disruptions and edge-localized modes) that can lead toloss of confinement and damage to the containment vessel and plasma-facing
components. Timely resolution of methods to predict, avoid, mitigate, and/or suppress
these events is a high priority for the world fusion program.

•

Taming the plasma-material interface: Controlling the interface between the hightemperature core of fusion plasma and the low-temperature surrounding material
structures is a high-priority scientific challenge. This includes understanding theformation of steep gradients in the interface layer, handling heat and particle exhaustfrom the core to the outside, and designing materials that can withstand thethermonuclear environment.

•

Experimentally validated, integrated predictive capabilities: Massively parallel
computing, grounded in experimentally validated theoretical models, will be hugely
valuable for enabling whole device modeling that can integrate simulations of physics
phenomena across a wide range of disparate time and space scales.

•

A fusion nuclear science subprogram and facility: Research in nuclear effects onmaterials (e.g., neutron irradiation) will be continued and enhanced, especially whenhigh-leverage opportunities for doing so can be captured. Due to funding

http://science.energy.gov/~/media/fes/fesac/pdf/2014/October/FESAC_strategic_planning_rept_dec14.pdf

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Department of Energy | December 2015
considerations, the DOE plan for fusion energy sciences research over the next decadedoes not include a major new fusion nuclear science facility, in contrast to FESAC 2014.

2.2: Community Workshops in 2015
The Office of Science listened carefully to community critiques of FESAC 2014 and has
responded by working with community leaders to develop a series of Research Needs
Workshops, which are being held during 2015. The results from these workshops will beincorporated when formulating the details for and executing future FES budgets.
Three of the five workshops being planned correspond to critical areas identified in the FESAC
2014 report as areas where increased emphasis would be beneficial as the fusion program
moves further into the burning plasma science era:•

Integrated Simulations for Magnetic Fusion Energy Sciences: Developing anexperimentally validated integrated predictive simulation capability that will reduce riskin the design and operation of next-step devices as well as enhance the knowledge
gained from ITER.

•

Transients: Understanding and controlling deleterious transient events that can disrupt
plasma operation and damage fusion devices.

•

Plasma-Materials Interactions: Addressing the extreme harshness of the burning
plasma environment at the plasma-materials interface and finding solutions.

Two other workshops will be held in a critical stewardship area:•

Plasma Science Frontiers: Including general plasma science, high energy density
laboratory plasma, and exploratory magnetized plasma, these workshops address the
Plasma Science Frontiers category in the restructured FES budget. The first workshop
will identify compelling scientific challenges at the frontiers of plasma physics, and thesecond workshop will identify research tools and capabilities, as well as the general
requirements necessary to address these challenges in the next decade.

The objectives of the five workshops include elements from among the following: (1) reviewing
progress and an update about new developments since the last time organized community
input was obtained, (2) identifying gaps and challenges, along with specific parameters thatwould need to be achieved for addressing such gaps, (3) discussing near- and long-term
research tasks, such as experiments that could be performed on existing facilities, (4) describing
upgrades to existing facilities and diagnostic capabilities that would enable or enhance theresearch tasks, (5) identifying linkages to associated research areas, (6) describing and analyzing
potential new activities for addressing the gaps and challenges, and (7) identifying areas forwhich modeling and simulation could be impactful.

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Department of Energy | December 2015

2.3: Previous Community Studies
A number of previous studies authored by the scientific community, including several Fusion
Energy Sciences Advisory Committee reports responding to charges from DOE, have been andcontinue to be important influences on the strategic direction of the Fusion Energy Sciences
program.
In 2002, a large community summer study held in Snowmass, Colorado, assessed three options
for burning plasma experimental facilities and indicated a preference for the international ITER
project.3 Later the same year, FESAC wrote A Burning Plasma Program Strategy to Advance
Fusion Energy. 4 This report observed that “there is an overwhelming consensus among fusion
scientists that we are now ready scientifically, and have the full technical capability, to embark
on this step” (viz., experimental study of a burning plasma).
In 2004, the National Research Council (NRC) of the National Academies of Science endorsed
U.S. participation in the ITER project with its report Burning Plasma: Bringing a Star to Earth. 5
The report stated: “There is now high confidence in the readiness to proceed to the burning
plasma step because of the progress made in fusion science and fusion technology. Progress
toward the fusion energy goal requires this step, and the tokamak is the only fusion
configuration ready for implementing such an experiment.” This report, together with the
Snowmass report and the 2004 FESAC report, helped propel the U.S. to formally rejoin the ITER
project. The Energy Policy Act of 2005 (P.L. 109-58) directed a follow-up NRC study of U.S.
participation in ITER, released in 2008, entitled A Review of the DOE Plan for U.S. Fusion
Community Participation in the ITER Program. 6Contemporaneously, DOE charged FESAC to undertake a broad study to identify the major
scientific knowledge gaps that must be overcome to achieve practical fusion energy. In 2007,
FESAC issued a report, Priorities, Gaps, and Opportunities: Towards a Long Range Strategic Planfor Magnetic Fusion Energy, which has proved to be a major influence on FES program
planning. 7 Emphasized in this report were challenges related to plasma transients, fusionmaterials science, and high-performance computing.
Also in 2007, FESAC considered the final report from the DOE-supported Fusion Simulation
Project Workshop and issued its own assessment: FESAC Fusion Simulation Project Panel Final
Report. 8 The same workshop output was also assessed in a report issued by the Advanced

3

http://fire.pppl.gov/snowmass02_report.pdf
http://science.energy.gov/~/media/fes/fesac/pdf/2002/Austin_final_full_2002.pdf
5
http://www.nap.edu/catalog/10816/burning-plasma-bringing-a-star-to-earth
6
http://www.nap.edu/catalog/12449/a-review-of-the-doe-plan-for-us-fusion-community-participation-in-the-iterprogram7
http://science.energy.gov/~/media/fes/fesac/pdf/2007/Fesac_planning_report.pdf
8
http://science.energy.gov/~/media/fes/fesac/pdf/2007/Fesac_fsp_report.pdf
4

Fusion Energy Science Program: A Ten-Year Perspective | Page 12

Department of Energy | December 2015
Scientific Computing Advisory Committee (ASCAC). 9 Although DOE ultimately did not support
the approach espoused in the 2007 Fusion Simulation Project vision, the FESAC and ASCAC
reports and related community activities have affirmed the readiness for making whole-device
modeling an FES priority.
The same year, the NRC completed its Plasma 2010 Decadal Report entitled Plasma Science:
Advancing Knowledge in the National Interest. 10 This report articulated the importance of
discovery plasma science as a core element of the FES program and affirmed FES’s role as aleading steward of this science for the nation.
In 2008, FESAC evaluated magnetic confinement configurations other than tokamaks. This
resulted in the Report of the FESAC Toroidal Alternates Panel. 11 The report underscores thecomplementarity of confinement science for systems ranging from compact toroids totokamaks to stellarators. The report also argued for continued support of research in threedimensional (3D) magnetic topologies, which is relevant to tokamaks (which have inherent andapplied 3D magnetic fields), as well as to stellarators as a potential future confinement concept.
An FES-sponsored workshop in 2008 led to the report Low Temperature Plasma Science: Not
Only the Fourth State of Matter but All of Them. 12 This report articulated the value of
supporting this class of research within the FES portfolio.
From June 2009 through January 2010, FES conducted a series of four Research Needs
Workshops (ReNeW), which resulted in the following reports: Research Needs for Magnetic
Fusion Energy Sciences (2009); 13 Advancing the Science of High Energy Density Laboratory
Plasmas (2009); 14 Research Needs for Fusion-Fission Hybrid Systems (2009); 15 and Basic
Research Needs for High Energy Density Laboratory Physics (2010).16 The HEDLP reports
underscored the high scientific value of this research, as well as the need for carrying it out on
well-diagnosed facilities that institute a user-facility model for program governance. For fusionfission hybrids, however, no major programmatic initiatives could be supported, given theavailable resources.
A community-led workshop at Princeton Plasma Physics Laboratory in 2010 led to the report
Research Opportunities in Plasma Astrophysics, 17 which outlined many opportunities.

9

http://science.energy.gov/~/media/ascr/ascac/pdf/reports/Ascac_fsp_report_final.pdf
http://www.nap.edu/catalog/11960/plasma-science-advancing-knowledge-in-the-national-interest
11
http://science.energy.gov/~/media/fes/fesac/pdf/2008/Toroidal_alternates_panel_report.pdf
12
http://science.energy.gov/~/media/fes/pdf/about/Low_temp_plasma_report_march_2008.pdf
13
http://science.energy.gov/~/media/fes/pdf/about/Magnetic_fusion_report_june_2009.pdf
14
http://science.energy.gov/~/media/fes/fesac/pdf/2009/Fesac_hed_lp_report.pdf
15
http://web.mit.edu/fusion-fission/Hybrid_Report_Final.pdf
16
http://science.energy.gov/~/media/fes/pdf/workshop-reports/Hedlp_brn_workshop_report_oct_2010.pdf
17
http://science.energy.gov/~/media/fes/pdf/about/Wopa_report_march_2011.pdf
10

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Department of Energy | December 2015
In July 2011, DOE charged FESAC to (a) examine the opportunities and various modes forcollaborations with the new billion-dollar-class international fusion facilities and (b) determine
the ways to strengthen the materials/nuclear science research areas, which, in conjunction withITER research operation, will enable the construction of a demonstration power plant. In
response to (a), FESAC wrote Opportunities for and Modes of International Collaboration in
Fusion Energy Sciences Research during the ITER Era (February 2012).18 This report emphasized
the value of such partnerships when carried out from a platform of a strong domestic program.
In response to (b), FESAC wrote Opportunities for Fusion Materials Science and Technology
Research Now and in the ITER Era, 19 which described a range of fusion materials sciencechallenges, both nuclear and non-nuclear. This report recommended initiating a linear highheat flux facility for materials testing, and partnering with a spallation neutron source for fusionmaterials nuclear research.
In April 2012, DOE charged FESAC to assess priorities among and within the elements of the
non-ITER part of the magnetic fusion energy sciences program, with special focus on researchthat supports burning plasma science, long-pulse/steady-state plasma operation, and fusionmaterials science. The report entitled Priorities of the Magnetic Fusion Energy Program(January 2013)20 made progress in prioritizing among the thrusts in the 2009 Research Needs
for Magnetic Fusion Energy Sciences report. Due to issues with conflict of interest, the report
did not answer the full charge. This effort served to segue to the FESAC 2014 report.
In 2013, DOE charged the federal advisory committees of all six Office of Science program
offices to evaluate facility priorities for the next decade. FESAC responded with Report of the
FESAC Subcommittee on the Prioritization of Proposed Scientific User Facilities for the Office of
Science (2013). 21 Although budget constraints will likely prevent the support of the full paletteof opportunities that were proposed in this report, its recommendations for upgrades of major
confinement facilities, as well as an increased emphasis on fusion nuclear materials science
research, were important.

18

http://science.energy.gov/~/media/fes/pdf/workshop-reports/20120309/Intl_Collab_Final_SCSC-PRINT.pdf
http://science.energy.gov/~/media/fes/pdf/workshop-reports/20120309/FESAC-Materials-Science-finalreport.pdf
20
http://science.energy.gov/~/media/fes/fesac/pdf/2013/Final-Report-02102013.pdf
21
http://science.energy.gov/~/media/fes/fesac/pdf/2013/FESAC_Facilities_Report_Final.pdf
19

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Department of Energy | December 2015

3. Research Directions
The framework for the FES decadal strategic directions mirrors the four major research
categories that define the FES program budget structure: foundational burning plasma science,burning plasma sustainment science, high gain burning plasma science, and discovery plasma
science. Within this framework, and considering input from FESAC and community planning
processes to date as discussed in Chapter 2, there are five areas of emphasis:
•
•
•
•
•

Massively parallel computing with the goal of validated whole-fusion-device modeling
Materials research as it relates to plasma and fusion science
Research in the prediction and control of transient events that can be deleterious totoroidal fusion plasma confinement
Stewardship of discovery in plasma science that is not expressly driven by the fusionenergy goal but will address frontier science issues
Robust operations support and regular upgrades of FES facilities.

3.1: Burning Plasma Science: Foundations
Goal
This research category advances the validated predictive understanding of plasma confinement,
dynamics, and interactions with surrounding materials.

Objectives(a) Burning plasma-relevant science – Answer urgent scientific questions – such as how tocontrol transient events – required for ITER to meet the needs of the ITER project and its
program once launched, including optimizing ITER operating scenarios and preparing
strong research teams capable of reaping scientific reward from the ITER experiment.
(b) Validated predictive modeling – Establish the basis for validated prediction andinterpretation of fusion experiments so as to be used as a world-leading tool forformulating ITER operational scenarios and also reducing the risk of development steps
between present-day research and a future demonstration reactor.
(c) Next-generation research capabilities – Develop the scientific basis for optimizing thecapabilities of next-generation research platforms.

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Department of Energy | December 2015

Strategic Implementation
The foundations of burning plasma science can be explored with the use of experimental
proxies for a true burning plasma state. Research at the major U.S. fusion experimental
facilities will be increasingly aimed at resolving fundamental advanced tokamak and sphericaltokamak science issues, including developing the predictive understanding needed for ITER
operations and providing solutions to high-priority ITER concerns.
In all funding scenarios, emphasis will be on upgraded DIII-D and NSTX-U working as acomplementary pair. Research will take advantage of their differing as well as overlapping
access to plasma parameters that are important for understanding burning plasma scienceissues relevant to ITER and to any future burning plasma experiment, including steps forfacilitating advanced fusion components testing.
The activities at these major facilities will also
support enhanced emphases for research on
potentially deleterious transients and plasmamaterial interaction science. As already noted,
the prediction, detection, control, mitigation,
and avoidance of deleterious plasma events,
including disruptions and edge-localized modes,
constitute a high-priority research initiative in
the Foundations area. This research will takeadvantage of present and upgradedinfrastructure at the DIII-D and NSTX-U tokamak
facilities, as well as on smaller-scale facilities asappropriate. The urgency of this research ismagnified by the U.S. having the responsibility todevelop and fabricate disruption mitigation
systems for use on ITER.

Turbulence simulations for low (left) and moderate aspectratio tokamaks (http://w3.pppl.gov/~hammett/viz/viz.html)

DIII-D and NSTX-U differ in the most important featurethat makes the tokamak an effective plasma
confinement device, namely, in their degree ofcompactness, as measured by the toroidal aspect ratio.
Exploration of the impact of this difference can informmuch of fundamental science pertaining to magnetic
confinement. Their similarities in many respects,
combined with this aspect ratio difference, make DIII-D
and NSTX-U a globally unique and complementary
powerful pair of fusion plasma research facilities.

Research in the Foundations area will also help to establish the scientific basis for research onsuperconducting long-pulse overseas facilities that are either already in operation or soon tooperate (cf. Section 3.2).
Per Congressional direction and consistent with the Administration’s recent budget requests,
operation of the Alcator C-Mod tokamak will cease at the end of FY 2016.
The research efforts on DIII-D and NSTX-U will continue to be joined by targeted studies on
smaller-scale advanced tokamak research and spherical torus facilities at universities andnational laboratories. Research on small-scale magnetic confinement experiments will be
useful to elucidate physics principles underlying toroidal confinement, test innovative methods,
and validate theoretical models and simulation codes.
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Department of Energy | December 2015
Modeling and simulation that capitalizes on the Office of Science’s world-leading capabilities inhigh-performance computing will be a high-priority research direction in the Foundations area.
The U.S. is a world leader in theoretical work on the fundamental description of magneticallyconfined plasmas and in the development of advanced simulation codes on current andemerging high-performance computers. Also, the U.S. fusion community has been adopting asystematic approach to verification and validation (V&V) and uncertainty qualification (UQ).
During the coming decade, increased emphasis will be placed on integrated whole-device
modeling based on massively parallel computation. This work will use multi-petascale
capabilities and target the future use of exascale capabilities in partnership with the Office ofAdvanced Scientific Computing Research. Research activities will drive integration of code
modules (e.g., stability, transport, equilibrium, etc.) that are currently separate. The two highlevel goals of whole-device modeling would be (1) the development of a robust, extensible
computational framework for the entire plasma cross-section (i.e., from the core to the firstwall) and (2) systematic validation of codes with the use of experimental data.
The extreme computational challenges confronted in developing simulation codes for fusion
plasma systems require the active involvement of applied mathematicians and computerscience experts, as well as access to leadership-class computing resources. Large-scale
numerical simulations and theoretical modeling will be valuable for attacking the two highpriority research areas already identified, namely, transients and plasma-material interactions.
The former is associated with the Foundations area, and the latter will be discussed in the Long
Pulse section. FES will explore partnership opportunities with the Advanced Scientific
Computing Research (ASCR) program in the Office of Science to support an integrated wholedevice modeling endeavor. Currently, FES jointly sponsors three fusion-related Scientific
Discovery through Advanced Computing (SciDAC) centers with ASCR and has a long history offruitful partnership. FES will also seek insight in large-scale computing and validation fromother research communities. Cooperation with our international partners and the ITER
Organization may also be valuable, as will access to validation data from long-pulse
superconducting tokamaks and stellarators overseas.
The Foundations area will also continue to support research on enabling technologies needed
to support the continued improvement of the experimental program and facilities. Examples ofthese enabling technologies are innovative magnet development and improved heating andfueling methods. The U.S. is the world leader in cryogenic pellet injection technology, used tofuel fusion plasmas and also to suppress disruptions and mitigate edge localized mode
instabilities, and will design and construct the ITER pellet injector system.
Support will continue for vital general plant infrastructure improvements at Office of Sciencelaboratories conducting fusion research.
The two major U.S. fusion research facilities, DIII-D and NSTX-U, complement each other due totheir different aspect ratios (defined as the plasma radial dimension compared to the major
radius size of the confinement device). This difference allows access to plasma parameters andFusion Energy Science Program: A Ten-Year Perspective | Page 17

Department of Energy | December 2015
operational regimes that both differ and overlap, which is highly advantageous forunderstanding burning plasma science issues relevant to ITER and any future burning plasma
experiment. In addition to the physics that is revealed by systematic studies of aspect ratio
variations, systems studies reveal that aspect ratio plays a fundamental role in the ultimate
economics of a magnetic confinement fusion reactor. During the next decade, these two
facilities will therefore be utilized to develop the scientific basis for optimizing the capabilitiesof next-generation research platforms.
One of the controversial recommendations of FESAC 2014 was to consider shutting down oneof these two major facilities midway through the decade in order to initiate a move toward
construction of a Fusion Nuclear Science Facility (FNSF). Although DOE recognizes the future
value of such a facility for pursuing vital research in the area of fusion nuclear science (andacknowledges its absence on the recent European fusion road map, which presents a gap
opportunity for the U.S.), the FES research plan for the next decade will not be predicated on
the beginning of design and construction of an FNSF. Foreseeable out-year budget constraints
make investment in the design and construction of an FNSF untenable.

3.2: Burning Plasma Science: Long Pulse
Goal
This research category explores new and unique scientific regimes that can be achieved withlong-duration superconducting fusion confinement machines and addresses the developmentof advanced materials required to withstand the extreme conditions in a burning plasma
environment.

Objectives(a) Sustainment of long-pulse plasma equilibria – Apply research on domestic confinement
facilities (managed in the Foundations area) to establish the basis for sustained plasma
operation and inform the long-pulse research conducted in partnerships onsuperconducting magnetic confinement facilities across the globe.
(b) Combined effects of high neutron fluences and high heat and particle fluxes – Enable
experimental access to the combined study of neutron irradiation and very high power
and particle fluxes, encountered in the burning plasma environment, and investigate
how these phenomena together affect plasma confinement and plasma-materials
interactions.

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Department of Energy | December 2015

Strategic Implementation
Understanding how to confine and control fusion plasmas during sustained discharges isessential expertise for U.S. scientists who may participate in research operations on ITER andfuture burning plasma experiments. This research frontier requires the leveraging of mature
U.S. research knowledge in the Foundations area into collaborative research activities carriedout on overseas facilities that have long-pulse capability enabled by superconducting magnet
technologies.
The world-leading superconducting fusion devices in Asia and Europe represent a state-of-theart capability that the U.S. does not possess on its copper coil fusion facilities, but in which it
can participate as a partner – and has been invited to do so. U.S. engagement is essential toprovide U.S. researchers with an opportunity to be among the leaders in this broad class of
fusion science.
At present, there are two U.S. teams focusing on the superconducting tokamaks in Asia andanother U.S. team focused on the superconducting stellarator in Europe. Contingent on theavailability of budget resources, U.S. collaborative research on international long-pulse facilities
may be expanded, with an emphasis on research that builds on scenarios and experiencedeveloped on the U.S. domestic facilities.
Many front-line research opportunities for U.S. researchers and students reside with ouroverseas fusion energy sciences partners. International partnerships in fusion science researchgo back decades, taking advantage of the great potential of mutually beneficial researcharrangements.
Through present-day partnerships, U.S.
scientists are already performing research on
overseas superconducting facilities that haveoperational capabilities beyond those of any
U.S. facility in some key respects. For
example, General Atomics has recently
demonstrated the capability for remotecontrol of the operation of thesuperconducting EAST tokamak in China,
applying advanced operating scenarios thatwere initially developed on the DIII-D
tokamak. Using both federal support and its
own investment of corporate funds, last year
General Atomics established a remotecollaboration center as a repository for EAST
experimental data, which can be accessed
and analyzed via ESNet by collaborators atseven other U.S. institutions. This enables a

Courtesy General Atomics

The viability of remote control of fusion plasmas operated
in overseas facilities has been demonstrated at General
Atomics in San Diego, CA. From there, scientists haveparticipated in controlling what is presently the longestduration high-confinement-mode plasma in the world,
created on the EAST tokamak at ASIPP in Hefei, China.

Fusion Energy Science Program: A Ten-Year Perspective | Page 19

Department of Energy | December 2015
new class of research in the U.S. wherein operating scenarios and diagnostic techniques aredeveloped stateside and then deployed and operated overseas. With opportunities properlychosen with our international partners, such an approach can advance the research objectivesof both U.S. scientists and our international colleagues.
In extending its research arms overseas, the U.S. fusion research enterprise may benefit fromlearning lessons from other branches of science where this leap has already been taken, such as
the fields of high energy physics and astronomy. Importantly, U.S. fusion research could evenset a standard for remotely controlled measurement and remote operation of experiments.
Indeed, U.S. researchers could have significant impact in helping to set the research agendas forthese emergent programs by means of vigorous engagement at the level of program planningand through a combination of off-site participation and on-site engagement. Also, theexperience gained from U.S. research teams that are based overseas may be invaluable for U.S.
scientists who will be participants on future international ITER research operations teams.
The Long Pulse area may also host enhanced research partnerships with international tokamak
research programs overseas that do not utilize superconducting magnets, most notably, theJoint European Torus (JET) program in the United Kingdom.
A high-priority objective during this decade is to combine research on materials effects on
plasma confinement (e.g., edge pedestal formation, and transport in the open field lines), highheat flux effects on materials, and neutron irradiation effects. The overall motivation is to gain
entry into a new class of fusion materials science wherein the combined effects of fusionrelevant heat, particle, and neutron fluxes can be studied for the first time anywhere.
Fusion materials research on neutron irradiation effects presently takes advantage of thefission-based High Flux Isotope Reactor (HFIR) user facility, located at Oak Ridge National
Laboratory. Along with research conducted on HFIR, FES will explore development of a newresearch platform that can study how material samples are impacted by neutron irradiation
with high rates of atomic displacements and an energy spectrum similar to that of a fusionenergy system, including neutrons at the 14-MeV fusion birth energy. FES will assess a variety
of fusion materials research platforms, including new test stands and point neutron sources, aswell as possible partnership with the Basic Energy Sciences program to access the Spallation
Neutron Source at ORNL. FES will welcome proposals from the community on other fusion
nuclear science research opportunities.
For dedicated studies of the effects of high heat and energetic particle fluxes on material
properties, linear test-stand experiments will continue to be very important. Emphasis will beplaced on development of a state-of-the-art linear test stand with the capability for analyzing
high heat flux effects on irradiated material samples, for upwards of 1000 seconds.
Linear test-stands enable long-pulse, high-heat-flux materials testing, but cannot address thegeometric effects of toroidal confinement. The interplay between plasma configurationdependent effects and plasma-material interactions will be studied by taking advantage of
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Department of Energy | December 2015
present and upgraded capabilities on the major U.S. fusion facilities. Also, cooperative fusionmaterials research will be conducted on overseas toroidal facilities that have long-pulse
capabilities and/or that have installed ITER-like metallic plasma-facing components.
In addition, high-risk/high-reward research on liquid-metal wall materials for tokamaks willcontinue, with the potential of fundamentally changing the nature of the plasma-materials
interface scientific challenge.
Throughout the decade, FES will continue to pursue partnerships with other SC programs, DOE
offices, and federal agencies in the area of materials science. Perhaps no other science andtechnology agency has a broader or deeper materials science R&D portfolio than the
Department of Energy. FES should seize the opportunity for the U.S. to be a world leader infusion materials science in the burning plasma era and beyond.
Throughout the Long Pulse research portfolio, strong linkages with massively parallel
computation will be emphasized. Also, to the degree that funding enables the creation of new
fusion materials science experimental platforms, FES will emphasize that they be operated
under a user facility model.

3.3: Burning Plasma Science: High Power
Goal
This research category pursues demonstrating the scientific feasibility of high-gain fusionenergy.

Objectives(a) U.S. contributions to the ITER project – In-kind hardware and support to the ITER
Organization for project construction.

Strategic Implementation
Currently under construction in France, ITER is the world’s flagship project for burning plasma
science. It is designed to create and study the science of the sustained burning plasma state forthe first time. ITER will enable a tremendous leap forward for fusion science since it will
provide scientific access to plasmas in the burning-plasma reactor regime. Expected to operate
for 20 years, ITER is designed to surpass the energy “break even” point and demonstrate
production of at least ten times the power used to heat the fusion fuel. While significant
technical progress has been made with large fusion experiments around the world, most ofwhich were constructed in the 1980s, it has long been obvious that a larger and more powerfulmagnetic confinement experiment would be needed to create and study the physical
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Department of Energy | December 2015
conditions expected in a fusion system and to demonstrate its feasibility. The idea tocooperatively design and build such a device originated from the Geneva Summit between the
United States and the former Soviet Union held in November 1985. During the 1980s and1990s, the U.S. participated in the conceptual design activity and, after a hiatus, joined the ITER
negotiations in early 2003. A formal international agreement adopted in 2006 by seven partner
Members – the U.S., European Union, Japan, Russian Federation, China, India, and South Korea– marked the formal inception of the project.
The 2013 Management Assessment report recommended a number of reforms andimprovements at the ITER Organization. Two major recommendations were the accelerated
appointment of a new Director-General and the creation of a resource-loaded schedule andbaseline. A new Director-General, Dr. Bernard Bigot, was appointed on March 5, 2015, and has
begun work on reforming the ITER Organization. He has also taken control of the preparationof the resource-loaded schedule and baseline, which is now expected in November 2015. We
look forward to the review and consideration of the revised baseline and schedule by the ITER
Members. While structural and management reforms have begun and will hopefully have theeffect of transforming the ITER Organization into a more efficient and effective construction
management organization, we acknowledge that it takes time to effect change and understandwhat the updated ITER cost and schedule will be.
Under the terms of the ITER Joint Implementing Agreement, the U.S. contributes a 9.09 percent
share of the construction costs and a 13 percent share of the operating costs and will beentitled to full and equal access to the science to be performed at ITER. Unlike other large
international scientific projects, the contributions of the ITER Members are mostly in-kind
hardware rather than monetary in nature. In practical terms, this means that the U.S. has thebenefit of domestically producing many of the major hardware components that constitute theU.S. in-kind contribution to the project.
The Congressional request for an FES strategic plan states that the “plan should assume U.S.
participation in ITER.” Assuming successful completion of ITER construction, the U.S. should bein a position to field a world-class ITER research team by the commencement of ITER operations
in order to reap the highest scientific return for the U.S. in the 2020s and 2030s. Achieving thisgoal will depend on maintaining an impactful U.S. burning plasma science research program inboth the Foundations and Long Pulse areas.

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Department of Energy | December 2015

3.4: Discovery Plasma Science
Goal
This research area explores the fundamental properties and complex behavior of matter in theplasma state to improve the understanding required to control and manipulate plasmas for abroad range of applications.

Objectives(a) General plasma science – Understand the behavior of non-neutral and singlecomponent plasmas, ultra-cold neutral plasmas, dusty plasmas, and micro-plasmas, aswell as the study of dynamical processes in classical plasmas including turbulence andturbulent transport, magnetic reconnection, and plasma waves, structures, and flows.
(b) High-energy-density laboratory plasmas – Investigate the structural and dynamical
behavior of ionized matter at extreme densities and temperatures.
(c) Exploratory magnetized plasma – Conduct research on complex, magnetized plasma
systems that spontaneously evolve toward a state of long-range order throughdissipative processes.
(d) Measurement innovation – Develop novel diagnostic techniques and their applications
to new, unexplored, or unfamiliar plasma regimes and scenarios.

Strategic Implementation
While discovery is woven throughout the Foundations, Long Pulse, and High Power burning
plasma research activities described above, the Discovery Plasma Science element of the Fusion
Energy Sciences program emphasizes broad investigation of plasmas for discovery itself, as well
as for non-fusion related applications. The interactions between discovery plasma science
research and fusion energy science-related research are rich and important. Indeed, plasma
science is not only the basic context in which is embedded the special application to the
production and control of fusion energy, but it is also fundamental to understanding the natureof visible matter throughout the cosmos.
Discovery plasma science is a multi-disciplinary endeavor that explores the extremes of theplasma state, ranging from the very small (several atom systems) to the extremely large(astrophysical plasma structures spanning light years in length), from the very fast (attosecond
processes) to the very slow (hours), from the diffuse (interstellar medium) to the extremely
dense (diamond compressed to tens of gigabar pressures), and from the ultracold (tens of
micro kelvin) to the extremely hot (stellar core). FES will continue to support research at the
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Department of Energy | December 2015
forefront of each of these ranges, challenging our ability to produce and measure matter at theextremes. Discovery plasma science will continue to be a high-priority research area. DOE
reaffirms the National Academies’ conclusion that the FES program is the lead federal stewardof this branch of science. 22 The FES commitment to discovery plasma science will also deepen
the connections between the fusion/plasma science community and other fields of science.
In general plasma science, FES will continue to invest in research facilities and activities toaddress astrophysical problems involving plasma phenomena such as dynamo behavior,radiative shocks, magnetic reconnection, turbulence, and stellar opacities. FES will continue toencourage research of controlled manipulation of the distribution of charged particles in lowtemperature plasmas, which are the basis for an ever-increasing array of practical applications
ranging from energy-efficient lighting to low-heat, chemical-free sterilization processes. Muchof this research will continue to be supported through FES’s joint partnership program inplasma science and engineering with the National Science Foundation, subject to review andwith an increased emphasis on university-laboratory partnership opportunities.
In high-energy-density laboratory plasma(HEDLP) science, FES will emphasize
research conducted on the Matter in
Extreme Conditions (MEC) instrument, oneof six end stations on the Linac Coherent
Light Source (LCLS) at SLAC National
Accelerator Laboratory. LCLS is a worldclass x-ray free electron laser facility
whose unique ultrashort- x-ray laser pulses
provide novel scientific opportunities in
HEDLP science. The MEC instrument has
The interior of the Matter under Extreme Conditions (MEC)
the potential to revolutionize our
instrument at the Linear Coherent Light Source (LCLS) at SLAC
understanding of laser-plasma interactions
National Accelerator Laboratory. The LCLS and a 200 TW laser
and the unusual plasma state calledsystem serve both to generate and also to interrogate highenergy-density plasma states. The laboratory has led the“warm dense matter” by exploitation offormation of a national user community to take advantage of
the LCLS x-ray beam as both a targetthe MEC resource, which enables first-of-a-kind research ofdriver and diagnostic. FES will support
the warm dense state of matter.
research using this facility throughcompetitive solicitations. FES has been supporting academic research awards through the
NNSA-SC Joint Program in High Energy Density Physics, although with recent constrained
budgets FES has had to withdraw its portion of the support for these activities in its budget
proposals to Congress.
In the sub-field of exploratory magnetized plasmas, FES currently supports a number ofuniversity-based small- to intermediate-scale magnetically confined plasma experiments. The

22

http://www.nap.edu/catalog/11960/plasma-science-advancing-knowledge-in-the-national-interest

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Department of Energy | December 2015
largest of these is the only reversed field pinch device in the U.S., which is conducive to plasma
confinement research and laboratory studies of astrophysical plasma phenomena. Other
smaller-scale experiments in this portfolio support validation and verification of codes andmodels.
The three program elements of general plasma science, high-energy-density laboratory plasma,and exploratory magnetized plasma support a rich and diverse portfolio of research at thefrontiers of plasma science, sharing many common intellectual threads with the potential for
broadening connections between the fusion energy sciences program and other scientific fields.
Cross-cutting research themes – such as magnetic self-organization, explosive instabilities,
turbulence and transport, correlations in plasmas, multiphase plasma dynamics, and plasma
acceleration – allow for an intellectual juxtaposition of these program elements. Using these
themes as the organizational structure, FES will hold workshops (cf. Chapter 6) to identify both
the grand scientific challenges in the plasma science frontier area and also the research needs
required to address them.
Innovative plasma diagnostics has been and should continue to be an area of U.S. strength in
the world fusion program. FES will continue to promote breakthroughs in plasmameasurement instrumentation and techniques through the development of diagnostics withthe spatial, spectral, and temporal resolution necessary to validate plasma physics models used
to predict the behavior of fusion plasmas. Advanced diagnostic capabilities successfully
developed through this activity will continue to be migrated, when mature, to installation andutilization on major domestic and international facilities, normally then becoming supported
under the Foundations and Long Pulse subprograms.
FES will continue to maintain a leadership role in the national stewardship of discovery plasma
science by leveraging access to best-in-class experimental facilities through partnerships with
the National Science Foundation (NSF), the National Nuclear Security Administration (NNSA),
and the Office of Science’s Basic Energy Sciences (BES) program.
In addition, FES will identify scientific opportunities of high impact in discovery plasma sciencethat require access to intermediate-scale facilities with larger, hotter plasmas and more
extensive diagnostic capabilities. Beyond the experimental and diagnostic challenges forintermediate-scale facilities, simulating such systems will require the development ofsophisticated modeling tools and use of advanced computing platforms.

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4. Funding Scenarios
The Congressional language requested that DOE assess priorities for the domestic fusion
program based on three budget scenarios with the fiscal year 2014 enacted level as the funding
baseline: (1) modest growth, (2) budget growth based only on a cost-of-living-adjusted fiscal
year 2014 budget, and (3) flat funding.
In the Office of Science charge letter to FESAC that resulted in the FESAC 2014 report, modest
growth was interpreted as two percent above the published OMB inflators for FY 2015 throughFY 2024, cost-of-living budget growth was based only on the published OMB inflators for thesame years, and the flat funding scenario was pinned at the FY 2014 enacted appropriationlevel.
In the following discussion, the funding scenarios are understood as an exercise to confront
choices and identify priorities.

4.1: Modest Growth Scenario
Burning Plasma: Foundations
For this funding scenario, priorities in this area include nearly optimal operation of the NSTX-U
and DIII-D user facilities, at about 22–25 run weeks per year. This level of utilization would
allow for vigorous experimentation, including expansion of research opportunities for university
scientists and students, as well as routine maintenance. These run weeks might be decreased
to accommodate the scheduling demands of major upgrades. Within a broad scientificresearch portfolio, such upgrades are envisioned to enable new investigations in plasmamaterials interactions and their impact on confinement beginning midway through this ten year
planning period, and to create a strengthened ability to simulate the burning plasma state on
DIII-D. The run weeks would also support significant experimental investigations of deleterious
plasma transients and their control on both NSTX-U and DIII-D.
Even under this modest growth budget scenario, it is unlikely that the construction of a new
fusion confinement device on the scale of any of the current major facilities could be
supported, since such construction would force an undesirable contraction of research portfolio
breadth, which was already severely impacted in the FY 2013 budget cycle.
Development of whole-device modeling through validated computing will also be a highpriority research element. Although details need to be assessed and will be continually
updated, it is anticipated that in order to successfully develop a whole-device modelingcapability that can impact the early ITER program, a level of effort in massively parallel
computing of about two-to-three times that presently supported by FES will be required over aten-year time span.
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Department of Energy | December 2015

Burning Plasma: Long Pulse
This funding scenario will enable research and development that, if successful, could yield thelaunch of a first-of-a-kind fusion materials science program by mid-2020s. Experimental
capabilities to be pursued include the development of a test stand that would enable the studyof materials evolution exposed to fusion reactor-relevant heat fluxes over long pulses (1000s of
seconds). Studies will also be supported early in this ten-year period to support the
deployment by mid-decade of a unique capability to expose materials to reactor-relevant
neutron fluences and energies. If both experimental approaches can be brought to fruition, thiswould enable the U.S. to be in a unique position in five years to study for the first time aspectsof the combined effects of long-time material exposure to fusion-reactor-relevant high heat
flux, high neutron fluence environments.
This funding scenario also supports growth in select internationally-based research endeavors,
with emphasis on those efforts that best position U.S. researchers to have an impact inresearch areas not presently accessible in the U.S., that take advantage of the foundational
work carried out within the U.S., and that have the best potential for exploiting novel remotecontrol and measurement capabilities.
Before the 2025 timeframe, the FES program does not expect to be able to initiate a major
multi-billion-dollar-class domestic facility, such as the Fusion Nuclear Science Facility (FNSF)
that was recommended in FESAC 2014. Still, fusion nuclear research issues of high generalimportance, which would be potentially relevant to an FNSF, will continue to guide scientificdirections during this decade.

Discovery Plasma Science
This research area would experience growth, with emphasis on new and existing intermediatescale facilities operated under a user facility model. The output from the research needs
workshops in 2015 (cf. Section 2.2) will be useful in identifying research opportunities.
Emphases will likely include first-of-a-kind studies in laboratory astrophysics, research leading
to detailed understanding of the transition from the material state to the plasma state, andresearch that promotes the fundamental understanding and control of low-temperatureplasmas, with potential application in industry. In all budget scenarios, FES will emphasize
plasma science research that has the broadest impact across the sciences.

4.2: Cost-of-Living Budget Growth Scenario
Under this more constrained scenario, the priorities are the same as in the Modest Growth
Scenario, but the pace at which deliverables can be realized will be decreased. The Cost-ofLiving Budget Scenario results in a smaller research effort, at a funding level that is 20 percent
less than that for the Modest Growth Scenario by the end of the decade. This impacts every
major research area. Compared to the Modest Growth Scenario discussed above in which
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Department of Energy | December 2015
overall research support is increased, the level of research effort in the Cost-of-Living Budget
Scenario is held flat due to inflation, and the following situation is envisioned.

Burning Plasma: Foundations
Research operations on NSTX-U and DIII-D are likely be reduced from the optimum level by
several run weeks per year, slowing research progress and reducing the availability of the
facilities as resources for students and researchers from universities.
Whole-device modeling based on validated, massively parallel computing would still be a highpriority goal, but the level of research would be reduced, so that what would have beenachievable in ten years would likely be delayed by several years. It is likely that code validation
efforts that use experimental data would be reduced compared to what would be possible in
the Modest Growth Scenario.

Burning Plasma: Long Pulse
Fusion materials research would be similarly reduced. Full usage of new experimental
capabilities in materials and fusion nuclear science would be pushed out to later in the decade.
Supporting computational work would be decreased. Substantial growth in international
partnerships would be unlikely.

Discovery Plasma Science
FES would maintain an emphasis on executing a shift towards research on intermediate scale
facilities under a user facility model, but the number of such facilities supported in this budget
scenario would be smaller. As above, an emphasis would be placed on plasma science researchthat has the broadest impact across the sciences.

4.3: Flat Funding Scenario
Under this most constrained budget scenario, the basic research priorities remain the same asabove, but the pace at which deliverables can be realized will be significantly decreased, andthe scope of the FES program overall will be substantially narrowed. The Flat Funding Scenario
results in a much smaller research effort, at a funding level that is 45 percent less than that for
the Modest Growth Scenario by the end of the decade.

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Department of Energy | December 2015

Burning Plasma: Foundations
Research operations on NSTX-U and DIII-D would be reduced by as much as 40 percent below
optimum by decade’s end. Priorities would remain research in plasma transients, albeit with asignificantly slowed pace of progress and an overall narrowing of the breadth of these activities.
Whole-device modeling based on validated, massively parallel computing would still be a highpriority goal, but research activities to drive integration of currently separate code modules
would be greatly diminished. Emphasis would remain on SciDAC-sponsored activities. It is
likely that efforts to validate codes with experimental data would be reduced, compared towhat would be possible in the two growth scenarios.

Burning Plasma: Long Pulse
Fusion materials research would be substantially reduced as compared to the effort envisioned
in either of the two other budget scenarios discussed above. Development of new
experimental capabilities would be pushed to later in the decade. Support for computational
materials research would be reduced compared to the other scenarios. Growth in international
partnerships would be reduced as compared to the other scenarios.

Discovery Plasma Science
Within this area, HEDLP research would likely be reduced from the level supported in the FY
2015 enacted budget. As in all budget scenarios, FES would emphasize plasma research thathas the broadest impact across the sciences.

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