Written Testimony of Mark Herrmann
Director, National Ignition Facility
Lawrence Livermore National Laboratory
Delivered to theCommittee on Science, Space, and Technology Subcommittee on Energy
United States House of Representatives
Hearing on the Future of Fusion Energy Research
March 6, 2018
Chairman Weber, Ranking Member Veasey, and Members of the Committee, thank you for theopportunity to appear before this committee and to offer testimony on the future of fusion energy
research. My name is Mark Herrmann, and I have been the Director of the National Ignition Facility(NIF) at Lawrence Livermore National Laboratory (LLNL) since 2014. Prior to becoming NIF Director, I
spent 9 years at the Sandia National Laboratories (SNL) holding a number of positions, including Directorof the Pulsed Power Sciences Center that is home to the Z Pulsed Power Facility. I have been involved ininertial confinement fusion research for 20 years, beginning my career at LLNL after completing mythesis research at the Princeton Plasma Physics Laboratory.
With my testimony, I hope to convey several points:
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The NIF, along with the Z Pulsed Power Facility, and the Omega Laser Facility at the Universityof Rochester, are world-leading scientific capabilities funded by the Inertial Confinement Fusion(ICF) Ignition and High Yield Program of the National Nuclear Security Administration (NNSA)
as part of the Stockpile Stewardship Program (SSP). All 3 facilities are providing experimental
data and workforce training in the high energy density regimes needed to maintain a safe, secure,and effective U.S. nuclear deterrent without further underground nuclear testing.
One of the major efforts of the national ICF program and the NIF is to achieve fusion ignition in
the laboratory to address a grand challenge established at the beginning of the stewardshipprogram. In 2016, NNSA established a 2020 goal for the ICF program to assess the efficacy of
NIF for achieving ignition. LLNL and the ICF community developed a 4-year plan to meet that
goal, and we are on track at the halfway point. Recently there has been exciting progress in theperformance of NIF implosions resulting in a doubling of the fusion yield.
If ignition can be achieved, it could pave the way to a broad, national, coordinated plan to pursue
Inertial Fusion Energy (IFE), which is an innovative, alternative path that is complementary to
mainstream magnetic fusion energy research. Currently IFE is not part of the long-term energy
R&D portfolio of the U.S. and is not being researched at LLNL.
The United States is the acknowledged world leader in the area of high energy density science,
thanks to investment by the NNSA and DOE, and broad collaborations are exploiting thesecapabilities to perform world leading science and develop advanced technology. However, theU.S. lead is rapidly shrinking and there are some subfields of HED research where the U.S. is
now behind.
The FY19 President’s Budget Request for the ICF program will lead to major reductions inexperiments at NIF and the closure of the Omega Laser Facility, substantially impacting ourability to support the Stockpile Stewardship Program, significantly delaying the pursuit of fusion
ignition, and disrupting the pipeline of future HED scientists and stockpile stewards.
The National Academy of Sciences Committee on a Strategic Plan for U.S. Burning Plasma
Research has recently released its interim report, which calls for a long term strategic plan forfusion energy.

The National Ignition Facility is delivering for the Stockpile Stewardship Program
Most of the yield of our thermonuclear weapons is generated in the High Energy Density (HED) state.
With the cessation of underground nuclear testing in 1992 and the creation of the Science Based Stockpile
Stewardship Program (SSP) in the 1990s, it was recognized that an enduring Stewardship Program would
require experimental access to HED regimes to ensure the U.S. nuclear stockpile remains safe, secure,and effective without further underground nuclear testing.
The three major U.S. HED facilities funded by the NNSA are NIF, the Z Pulsed Power Facility at SNL,and the Omega Laser Facility at the University of Rochester. These facilities work together incomplementary ways to perform the scientific experiments needed for the SSP.
NIF is a football-stadium-sized facility that houses the world’s most energetic laser, (approximately 60
times more energetic than any other laser in the world when it was completed in 2009). NIF’s 192 lasers
can focus into a target smaller than a dime, creating conditions hotter and denser than those found at thecenter of the Sun. NIF is being used by stockpile stewards at all three weapons laboratories to obtain
critical data in support of the SSP. For example, experiments on NIF are:••••Illuminating key weapons physics issues left unanswered when underground testing stopped,enabling sustainment of the current U.S. nuclear stockpile.
Providing information that is used to develop and certify the approaches to modernizing our U.S.
nuclear weapon systems without additional underground explosive nuclear testing.
Ensuring the nation is aware of and can assess advances in the nuclear weapons of other nations
and avoid technological surprise.
Providing experimental data that enables tests of our numerical simulation design codes and isused for the physics models critical to the predictive capability that underpins the science-based
SSP.

Over the last four years we have doubled the rate of experiments on NIF, despite flat funding, helping to
reduce oversubscription for this unique capability in the world. Recent accomplishments for the
Stewardship Program include:•••

LLNL scientists have performed experiments to measure the behavior of plutonium at highpressure for the first time --- previously, only theoretical predictions existed. Experimental dataagrees with theory in some regimes and differs from theory in others.
Los Alamos National Laboratory(LANL) scientists have applied NIF to study the hydrodynamic
evolution of sheared flows in never before accessed, relevant regimes. These experiments have
led to the development of new models to be consistent with the experimental data.
SNL scientists have used NIF to study the effects of large x-ray and neutron bursts on test objects
to help validate codes that are used to ensure our system’s nuclear survivability.

In addition to the experimental data that HED facilities like NIF provide, they also play a major role inrecruiting and training the scientists and engineers who are the next generation of stockpile stewards. In theabsence of underground nuclear testing, NIF experiments, particularly ignition experiments discussed
below provide an important training ground for our current and future workforce in the skills needed to be
successful as stockpile stewards. This experience is so valuable that, in fact, many of the current leaders of
the SSP have participated in various aspects of the national ICF program.

NIF is on track to meet the NNSA milestones laid out for fusion ignition research in 2020
At the beginning of the SSP, a grand challenge goal was set of achieving ignition in the laboratory, toaddress the most challenging outstanding questions in weapons physics. NIF is the only fully operational
facility in the world that is capable of achieving thermonuclear fusion ignition in the laboratory via
inertial confinement fusion (ICF). Like magnetic confinement fusion research, ICF research focuses onheating a deuterium-tritium plasma up to the extreme temperatures (>50,000,000K) needed for the fusion
reactions to self-heat the plasma, potentially leading to the release of more energy than was invested in
the creation of the plasma. Unlike magnetic confinement fusion, which uses a large magnetic field in alarge volume to confine the plasma, inertial confinement fusion relies on the inertia of the deuterium andtritium fusion fuel squeezed to incredibly extreme conditions (higher density and pressure than the centerof our Sun) to provide the confinement.
Thermonuclear fusion ignition is a process that is critical for our nuclear weapons but is tremendously
difficult to achieve with the energy levels available in the laboratory. Pursuit of thermonuclear fusion
ignition in the laboratory provides the U.S. with insights into one of the least understood aspects of ourmodern nuclear weapons by providing experimental data to compare with our modern simulations, giving
us critical insights into similar processes taking place in our weapons. In addition, the achievement of thisgrand scientific challenge, would open entirely new vistas of high energy density science and enable
access to regimes even more relevant for stockpile stewardship in the future.
In a NIF ICF experiment, the powerful laser beams are directed into the inside of a hollow cylinder ofgold (about the size of a pencil eraser) forming a miniature x-ray oven. Inside the cylinder, the x-rays
heat a BB sized plastic capsule that contains the thermonuclear deuterium and tritium fuel, causing it to
implode on itself at close to one million miles an hour and shrinking in size from a peppercorn tosomething 1/10 the size of the period at the end of this sentence. This implosion generates the extreme
conditions needed for thermonuclear fusion reactions to take place. Our best simulations using our mostpowerful computers suggest that given sufficient control over the implosion, fusion ignition will takeplace and lead to the release of significantly more energy than the laser energy NIF used to create theimplosion.
Early experiments ending in 2012 fell far short of achieving fusion ignition, despite optimistic projections
from our best simulations at that time. A number of additional experiments were then performed to
identify the gaps in our simulation capability. In 2015, NNSA chartered a review of the national ignition
effort, and based on that review NNSA released a report in 2016, setting up a principal goal of theignition effort “by 2020, to determine the efficacy of NIF for achieving ignition and the credible physics
scaling to multi-megajoules of fusion yields for each of the major ICF approaches”.*
The LLNL ignition program, in partnership with LANL, is now half-way through the plan that wasdeveloped in response to NNSA’s 2020 goal. As part of that plan - by utilizing clever experiments,
advanced diagnostics, and new target designs - we’ve made a number of significant advances inunderstanding that have translated into improved implosion performance and higher fusion yield.
In fact, in 2017, changes to the targets used in the experiments enabled the fusion yield in the best
implosions on NIF to more than double the previous record, to over 50 kJ, or 25x higher than fusion
yields in 2012. The best implosions have demonstrated that the fusion plasma is starting to heat itself, acritical step on the path to ignition and akin to trying to light a campfire and having the wood start tosmoke. Current supercomputer simulations suggest that a 30% enhancement in the pressure or the*

NNSA report DOE/NA-0044, 2016 Inertial Confinement Fusion Program Frameworkconfinement time of this extreme plasma would bring us to the ignition threshold, although it is importantto keep in mind that while these simulations are the best we know how to do - they could be wrong.
Furthermore, there are a number of exciting avenues to pursue as we execute the plan to the 2020 goal.
New target designs with bigger and better capsules are opening up larger parameter spaces forexperiments, new diagnostics are shedding light on the differences between simulations and experiments,
and advances in the science and technology of the NIF laser have opened up pathways to a 40% increasein laser energy, which further broadens the space for ignition.
Ultimately the goal of the ignition effort on NIF is two-fold: to achieve ignition (greater than a megajouleof fusion yield) if it is possible, or to determine with high scientific confidence what is preventing ignition
on NIF. In the event that ignition is not attainable on NIF, it is critically important that we understandwhy, as it is essential for the SSP to be aware of this shortfall in our capabilities. It also prepares us forthe possibility of using alternate means to achieve ignition, either by modifying NIF or by developing
another ignition capable facility.
Progress on Inertial Confinement Fusion could provide an alternative path to fusion energy
If inertial confinement fusion ignition is obtained on NIF, it would be the first time in the laboratory that afusion reaction released more energy than was used to generate the reaction. Such a breakthrough could
form the basis of a possible path to fusion energy that would have significantly different technologicaland engineering risks than the concepts being pursued for magnetic fusion energy. To be clear, however,
NNSA does not have an energy mission and, therefore, no NNSA resources are being used for IFE
research at LLNL.
It is important to acknowledge upfront, like all approaches to fusion energy, that there are a large numberof technological, engineering, and scientific challenges to IFE. An IFE system would work by using adriver (such as a laser) to implode an injected target to fusion ignition and yield conditions multiple times
per second. There are very significant technical hurdles that would need to be overcome in developing
drivers that can operate multiple times per second, in building and injecting ignition quality targets
multiple times per second, and in protecting the entire system from the harsh fusion environment
associated with large, repeated fusion yields. Furthermore, each of these systems will have to be
developed at significantly reduced costs from current levels in order for any energy produced to beeconomical.
The National Academy of Sciences studied this problem and released an excellent, detailed report in 2013
entitled “An Assessment of the Prospects for Inertial Fusion Energy”.† A number of conclusions andrecommendations were made, including a recommendation to continue progress in target physics researchon the various approaches to inertial confinement being pursued on NIF, Z, and Omega facilities. The
report was clear in concluding that “The appropriate time for the establishment of a national, coordinated,broad-based inertial fusion energy program within DOE would be when ignition is achieved”.‡ In my
opinion a national, coordinated, broad-based IFE program should await fusion ignition.
Nevertheless the committee also concluded: “The potential benefits of energy from inertial confinement
fusion (abundant fuel, minimal greenhouse gas emissions, and limited high-level radioactive waste
requiring long-term disposal) also provide a compelling rationale for including inertial fusion energy
R&D as part of the long-term R&D portfolio for U.S. energy. A portfolio strategy hedges against†

An Assessment of the Prospects for Inertial Fusion Energy, Committee on the Prospects for Inertial
Confinement Fusion Energy Systems, NRC (National Academies Press, Washington, D.C., 2013).
‡
Ibid.

uncertainties in the future availability of alternatives such as those that arise from unforeseen
circumstances.”§
The idea that a portfolio strategy should include inertial fusion energy R&D is an important conclusion of
the NAS report. This is particularly true because the DOE is in an excellent position to make rapid
progress in this area by leveraging the large investment being made in many emerging technologies andby the NNSA in ICF research.
As an example of the benefits that would accrue from a small IFE portfolio, a number of promisingtechnologies highlighted in the NAS report as key to eventual IFE systems are making steady progress. In
particular, there have been exciting advances in rep-rated laser technology and rep-rated pulsed power
technology in the U.S. over the last few years, potentially lowering the cost of a future driver for an IFE
system. Additive manufacturing and other automated manufacturing techniques are becoming more costeffective and are being used as part of the current target fabrication effort on NIF. Research in themagnetic fusion community is advancing the potential of liquid metals as first wall materials for fusion
reactors, which could also benefit IFE. Unfortunately, without even a minimal IFE program, the U.S. is
not in a position to assess the significance of these advances for a potential future IFE system.
The U.S. is the world leader in high energy density science, although that lead is rapidly shrinking
As discussed above, the U.S. investments supported by NNSA and the DOE have made the U.S. theworld leader in this area of science, giving the U.S. a competitive advantage and demonstrating to theworld our commitment to maintaining a safe, secure, and effective deterrent. As an example, whencompleted in 2009, NIF operated with 60x more energy than the next biggest laser in the world, which
was the Omega Laser Facility, also in the US. Now, nearly a decade later, NIF operates with 10-20x theenergy of the next most energetic laser, which is in China. A very similar statement could be made about
the Z facility 10 years ago, with the second most energetic pulsed power facility located in the U.S. in2009 and in China today. There are few fields of science today where the U.S. has had, and currently
maintains, such a large lead over the rest of the world. This lead exists not only in facility capabilities but
also in diagnostics, targets, simulations, and scientific output and publications. This world leadershipalong with the compelling scientific opportunities - especially the grand challenge of inertial confinement
fusion ignition and the potential of a path to inertial fusion energy - has been a magnet for the best andbrightest scientists and engineers to pursue research in HED science and to work as part of the SSP.
To ensure healthy engagement with the outside community NNSA, has established cooperative research
programs on NIF, Omega, and Z that provide a small fraction of the facility experimental time toacademic researchers at other institutions. The proposals are judged on their scientific merit and technicalfeasibility by external scientific committees and the outside researchers are awarded time on NIF, Omega,
and Z to leverage these incredible investments for fundamental scientific studies. For example, academic
researchers on NNSA facilities have been studying how the fundamental properties of matter change as
the materials are squeezed to higher and higher pressures. These questions are of fundamental scientificinterest, are important to understand the structure of planets, and could possibly lead to the discovery of
new materials with unique properties and potentially commercial applications.
Such science is also of high interest in the world wide academic community and publications from thesecooperative research programs frequently appear in Nature, Science, and Physical Review Letters, andother prestigious journals. This research and these publications are an avenue for NNSA researchers tointeract with the outside world, and a very effective advertisement for recruiting students to the
Laboratories and into the SSP. Furthermore, the world-class research that our Lab scientists are
§

Ibid.

publishing is one of the most visible manifestations of our deterrent, since the credibility of the deterrent
ultimately rests on the quality of the people in the stewardship program. Last but not least, several ofthese academically-led experiments have developed new and innovative approaches to HED science thathave then been adopted for use in addressing core SSP questions.
The world leading nature of NNSA’s ICF facilities requires cutting edge science and technology, that inturn leads to many spinoff benefits. For example, NIF requires unique capabilities in lasers, optics,
precision target fabrication, diagnostics, and computer controls. Developments in these areas have led to alarge number of R&D 100 awards over the years and a proliferation of ideas that support our national
security (e.g. direct energy weapons) and our economic competitiveness (e.g. Extreme Ultraviolet
Lithography).
While historically we have had an impressive lead in HED science, it is clear today that the rest of theworld is aggressively focusing on catching up. Currently, megajoule (NIF) scale lasers are underconstruction in both France and Russia. The Chinese have completed and are operating the second mostenergetic laser in the world and are publishing papers with designs for lasers 50% to three times the sizeof NIF (note that having more energy makes achieving inertial confinement fusion ignition easier).
The area of high intensity lasers is a particularly noteworthy example. Researchers in the U.S. pioneered
the field of high intensity lasers. These lasers reach more extreme conditions not by increasing the energy
delivered, but by reducing the duration of the laser pulse, achieving higher and higher powers as theduration is reduced. In the 1990’s, LLNL broke the petawatt (10^15 watts) barrier with the constructionof the Nova Petawatt. A number of novel and important new properties emerged at the high intensities
that these new lasers enabled, and since then dozens of petawatt class lasers have been built andthousands of publications on the exciting science in this area were published over the next 20 years. In
December, the National Academy of Sciences published a report on “Opportunities in Intense Ultrafast
Lasers: Reaching for the Brightest Light”. A key conclusion from this report is that the:“The U.S. has lost its previous dominance. The United States was the leading innovator anddominant user of high-intensity laser technology when it was developed in the 1990s, but Europe
and Asia have now grown to dominate this sector through coordinated national and regional
research and infrastructure programs. In Europe, this has stimulated the emergence of theExtreme Light Infrastructure (ELI) program. At present, 80 to 90 percent of the high-intensity
laser systems are overseas, and all of the highest power (multi-petawatt) research lasers currently
in construction or already built are overseas”.**
The FY19 President’s Budget Request (PBR) for the Inertial Confinement Fusion Program will
significantly delay pursuit of fusion ignition as a goal for the SSP, make significant cuts to the
National Ignition Facility, and lead to the closure of the Omega Laser Facility.
NNSA’s FY19 PBR reduces funding for the national ICF program by more than 20% relative to FY17, a
reduction of more than $100M nationally, and reduces funding for the ICF Program at LLNL by $59M$73M (depending on final FY18 funding level and including effects of cost shift for target fabrication).
The budget request also includes drastic cuts to the Laboratory for Laser Energetics at the University ofRochester, an essential partner for LLNL, NIF, and the national ICF program. In particular, the request
for LLE is $45M, a reduction of $28M-35M (depending on final FY18 funding level and including costshift for target fabrication). The budget document states that the Omega Laser Facility will be closed overthe next three years. The target fabrication budget for General Atomics and Schafer, which have been**

Opportunities in Intense Ultrafast Lasers: Reaching for the Brightest Light, Committee on
Opportunities in the Science, Applications, and Technology of Intense Ultrafast Lasers; NAS (National
Academies Press, Washington, D.C., 2017).

strong partners in enabling many of the advances of the national ICF program for decades, has been
zeroed. Finally, the academic programs that are key to the field’s future are reduced from $9.5M tozero. Coupled with the reductions at the Omega Laser Facility, where many academics and theirstudents perform their research, these cuts cripple our academic partners and could lead to the loss of ageneration of graduate students doing research in the field of HED science and discourage students andearly career scientists from pursuing careers in this area of HED science.
LLNL is working closely with NNSA and our national partners in the ICF Program to minimize theimpact of these cuts should they be enacted and to remain focused on the highest priority deliverables for
the SSP. A detailed implementation plan has not yet been developed, but it is our assessment that
reductions in funding of this magnitude to the ICF Program will lead to major disruption and reduction in
our ability to provide the data needed in support of both near- and long-term SSP deliverables. We also
assess that the cuts will significantly delay the pursuit of fusion ignition and yield on the NIF, and means
we will not meet the NNSA goal set out for 2020. At LLNL, the proposed budget eliminates funding fornearly half of the scientists and engineers working on the ignition effort, representing a significant portionof the U.S. expertise in this area. Since almost every HED experiment supporting SSP has arisen fromtools or capabilities initially developed to address the grand scientific challenge of ignition, these cuts willaffect the long-term prospects for providing the data needed for the Stewardship program, and negatively
affect recruitment and retention of stockpile stewards.
The proposed cuts at LLNL, coupled with the reduction at other sites, will impact every aspect of theoperations of NIF. They will lead to a reduction in operating hours and experiments performed (>30%) as
resources are shifted to maintain critical skills and fill needed capabilities lost by reductions to partner
institutions. The reduction in experiments performed will impact all users of NIF, reducing opportunities
for stockpile stewards, greatly reducing ignition research, and reducing opportunities for the academic
community and users pursuing other important national security applications on NIF. NIF will also needto significantly reduce its peak laser power and energy, affecting the fidelity of many experiments.
Unique experimental capabilities that have been developed for addressing challenging weapons physics
issues will need to be placed in cold standby. As such, these proposed reductions will lead a degradationof NIF’s capabilities over time. The cuts to the University of Rochester Laboratory for Laser Energetics
will eliminate the efficient development of new experimental platforms on Omega that are eventuallyfielded on NIF, significantly increasing the time it takes to develop platforms needed for weapons
physics.
Obviously, if these cuts were to be enacted it would be devastating to our field with impacts beginningtoday and persisting well into the future. When viewed through the lens of developments around theworld, these reductions would slow the U.S. down significantly at a time when the rest of the world isaccelerating.
The National Academy of Sciences Committee on a Strategic Plan for U.S. Burning Plasma
Research has recently released its interim report.
While the focus of my own research for the last 20 years has been on inertial confinement fusion, I haveremained an interested observer in all aspects of fusion energy research. Currently, I am serving on the
National Academy of Sciences Committee on a Strategic Plan for U.S. Burning Plasma Research which is
focused on magnetic fusion energy research. Our committee, Co-Chaired by Professor Michael Mauel,
Columbia University, and Professor Mel Shochet, University of Chicago, has recently released its interim
report and is working now on the final report.

A brief summary of the main assessments from our interim report follows††:
Any fusion strategy requires a burning plasma experiment.
If the U.S. wishes to maintain leadership in this field, it needs to develop its own
long-term strategic plan for fusion energy.
Major Assessment:• The only existing project to create a burning plasma at the scale of a power plant is ITER, which
is a major component of the U.S. fusion energy program.
• As an ITER partner, the United States benefits from international cooperation to combine thescientific and engineering expertise, industrial capacity, and financial resources.
• A decision by the United States to withdraw from the ITER project could isolate U.S. fusion
scientists from the international effort and would require the United States to develop a new
approach to study a burning plasma.
Why is Burning Plasma Research Important?
Burning plasma research is essential to the development of magnetic fusion energy and contributes toadvancements in plasma science, materials science, and the nation’s industrial capacity to deliver hightechnology components. All efforts to make fusion energy require a burning plasma—an ionized gas likethe Sun and stars that is heated by fusion reactions. Although significant fusion power has been created in
the laboratory, a burning plasma, which is heated predominately by fusion reactions, has never beencreated.
In addition to a burning plasma experiment, further research is needed to improve and fully enable thefusion power system.
Status of U.S. Burning Plasma Research:• The U.S. fusion energy science program has made leading advances in burning plasma sciencethat have substantially improved our confidence that a burning plasma experiment such as ITER
will succeed in achieving its scientific mission.
• Recent closures of domestic experimental facilities without new starts, as well as a reduction offusion technology efforts, threaten the health of the field in the United States.
• Although our international partners have national strategic plans leading to a fusion energy
demonstration device, the United States does not.
If the United States wishes to maintain scientific and technical leadership in this field, thecommittee concludes that the United States needs to develop its own long-term strategic plan for fusionenergy. In the development of the final report, the committee views the following elements as important
to its guidance on a long-term strategic plan:• Continued progress towards the construction and operation of a burning plasma experimentleading to the study of burning plasma,• Research beyond what is done in a burning plasma experiment to improve and fully enable
commercial fusion power,• Innovation in fusion science and technology targeted to improve the fusion power system as acommercial energy source, and• A mission for fusion energy research that engages the participation of universities, national
laboratories, and industry in the realization of commercial fusion power for the nation.

††

Interim Report of the Committee on a Strategic Plan for U.S. Burning Plasma Research. (National
Academies Press, Washington, D.C., 2017)