Science-Watching: From Ignition to Energy

[from Science & Technology Review July/August 2025 Research Highlights, by Noah Pflueger-Peters]

Achieving ignition at the National Ignition Facility (NIF) proved that harnessing the power of the Sun in a laboratory may be possible. The Sun’s extreme temperatures and pressures cause light elements to fuse together to create heavier ones, releasing enormous energy and sustaining conditions for more thermonuclear reactions. NIF replicates these conditions with inertial confinement fusion, in which lasers compress and heat a target capsule filled with deuterium and tritium (DT), “heavy” isotopes of hydrogen that contain extra neutrons. When the isotopes fuse, they create helium and a neutron, and the lost mass is converted into inertial fusion energy (IFE), which can be harnessed for energy production.

Nuclear fusion produces significantly more energy than either nuclear fission or burning fossil fuels for equivalent amounts of fuel. Since the input materials for fusion energy are plentiful on Earth, an IFE power plant could produce safe, abundant, power grid-compatible energy without highly radioactive byproducts.

Although significant work remains to harness fusion energy, pursuing the development and deployment of IFE is crucial for the nation’s energy security, enabling the United States to shape implementation worldwide, avoid technological surprises from adversaries, and influence technical leadership in other energy-intensive technologies such as AI, machine learning (ML), and supercomputing.

IFE research stretches back to the early days of Lawrence Livermore, and today the Laboratory is fostering the overall fusion ecosystem. Livermore’s unique capabilities, expertise, and connections will be critical to laying the technical, logistical, and legal groundwork to make IFE possible. “IFE is a grand scientific and engineering challenge, something that is so incredibly difficult and high-risk and takes enormous expertise,” says Tammy Ma, Livermore’s IFE Institutional Initiative lead. “This challenge makes it the right kind of problem for national laboratories to pursue.”

This artist’s rendering shows the concept for an inertial fusion energy (IFE) power plant design, with a cutaway to show the plant’s target chamber in the center. Livermore researchers are laying the groundwork for private fusion companies to build similar designs. (Illustration by Eric Smith.)

Designing for Viability

NIF is the only facility to date to demonstrate the ignition and burning plasma conditions that are prerequisites for IFE, but it is an experimental facility for stockpile stewardship research, not a power plant. To be commercially viable and produce the energy to offset costs and meet demands (baseload power), IFE plants will need to generate more than 30 times the energy they deliver to the fusion target on every shot while firing 10 or more shots per second, compared to NIF’s rate of one or two shots per day.

The Laser Inertial Fusion Energy (LIFE) study, conducted between 2008 and 2013, aimed to build directly on technology developed for NIF to achieve IFE and took a systematic approach to this requirement by developing the Integrated Process Model (IPM). (See S&TR, April/May 2009 [archived PDF], pp. 6-15.)

IPM is a technoeconomic model of an IFE power plant with detailed technical and cost breakdowns and interdependencies of key systems and subsystems. “The work done under LIFE was fantastic,” says Ma. “IPM lays out engineering and physics requirements for the entire system to test out different scenarios and see the impact. Now, we not only get to expand on all that but also leverage 15 years of new data from NIF, better codes, and high-performance computing (HPC), as well as new work in AI, ML, advanced manufacturing, diagnostics, and nonproliferation across the Laboratory.”

IPM describes an IFE power plant that requires a solid-state laser driver system to “pump” lasers with optical energy using laser diodes instead of flashlamps as at NIF. The plant will also need to fabricate and fill target capsules onsite and send them into its target chamber at a high enough frequency to produce baseload power. “We will have to repeatedly inject targets into the chamber, so the targets must be able to withstand and survive that process,” explains Ma. “Then, the lasers will track the moving targets, and when one gets to the center of the chamber, they would fire on the centered target, repeating 10 to 20 times per second.”

The facility would convert fusion energy into heat and then electricity via steam turbines, sending most of the electricity to the power grid and recycling the rest to power operations on subsequent shots. Neutrons from the reaction would produce tritium needed for the DT fuel by bombarding lithium isotopes in a “breeding blanket” material lining its target chamber. By closing both the power and fuel cycles, IFE plants are expected to be self-sustaining.

Thanks in part to IFE STARFIRE (IFE Science and Technology Accelerated Research for Fusion Innovation and Reactor Engineering), a Department of Energy (DOE)-funded multi-institutional IFE research and development hub, researchers across the Laboratory are working to meet the new system’s demands. IPM can help identify key challenges, test the viability of new designs, and direct future research. “Many technical models and cost models exist for IFE, but very few, if any, pair systems and cost models together at the same depth as IPM,” says Mackenzie Nelson, a technoeconomic systems analyst in the Computational Engineering Division. “This type of tool offers such an advantage because we can assess design choices from both a technical and economic standpoint and create blueprints for what an IFE plant could look like.”

(left to right) Livermore researchers Bassem El Dasher, Claudio Santiago, and Mackenzie Nelson discuss a 3D model of a proposed IFE power plant design alongside the Integrated Process Model (IPM). IPM has more than 270 potential user inputs that researchers and collaborators can use to assess different IFE design choices to see the technical and cost impact on the entire design.

Operational Demands

NIF’s target capsules are extremely precise, fragile, and can take weeks to fabricate, fill, and position. Researchers are trying to reconcile that factor with the estimated demand of more than 800,000 capsules per day produced at less than $0.50 each to achieve IFE plant viability. To do this, they are examining optimal target designs for IFE and exploring advanced manufacturing methods such as microfluidics, volumetric additive manufacturing, and two-photon polymerization. (See S&TR, April/May 2025 [archived PDF], pp. 16-19.) Additional projects involve developing diagnostic instruments that can collect, analyze, and combine data with other diagnostics at the 10 to 20 shot per second frequency and use it to improve lasers in real time.

Fusion energy systems such as IFE are also a regulatory challenge, as they generate high-energy neutrons capable of breeding plutonium or uranium-233 and rely on large quantities of tritium. “Pure fusion energy systems do not require fissile material, but there are still ways to misuse these technologies that pose proliferation risk,” says Yana Feldman, the associate program leader for international safeguards. Bad actors may only need small amounts of tritium to make nuclear weapons, and some breeding blanket designs may inadvertently produce traces of plutonium that may be diverted for military purposes.

Nuclear fission reactors are regulated through international agreements and export control rules, and the independent International Atomic Energy Agency (IAEA) verifies that nuclear material and facilities are only being used for peaceful purposes. Neither treaties nor the IAEA address fusion energy, and no consensus has been reached on whether fusion energy systems need an international verification program. Verification methods for safeguarding tritium are also far less developed than for plutonium and uranium and focus more on contamination and transfers than analytical accounting for discrepancies. The precise scale of allowable tritium unaccounted for without posing proliferation risk is also unclear.

Fusion systems can be designed for proliferation resistance, but not having an existing design remains a challenge.

International security analyst Anne-Marie Riitsaar and her colleagues are exploring these complexities and starting conversations with international fusion experts and private industry to raise awareness. Riitsaar also plans to collaborate with the IPM team to map tritium diversion vulnerabilities and identify high-risk points where researchers could incorporate surveillance methods into plant designs to detect and prevent potential misuse. “People sometimes ask me why I’m thinking about fusion energy regulations and proliferation risks at this point, but it’s not too early,” says Riitsaar. “Reaching a multinational consensus on regulating sensitive technologies takes considerable time and effort.”

The National Ignition Facility is an experimental facility and not a power plant, so a commercial IFE plant design has vastly different requirements—many of which are being studied by Livermore researchers and their collaborators.

NIFViable IFE plant (estimated)
Repetition rateOne shot per day10 to 20 shots per second
Energy gain4.13 times (as of April 2025)30 times (minimum), 50 times to 100 times (ideal)
How lasers gain energyFlashlampsDiode pumping
Target fabrication and fuel fillingFabricated offsite over several weeks and filled manually in 1 to 5 daysMass-manufactured and filled in a target factory within the facility
Target deliveryPositioned manually within the Target ChamberShot into the plant’s target chamber approximately 10 to 20 times per second
Laser alignmentComputationally in real time, taking up to 8 hoursIn real time
Power cycleOpen, requiring outside energy sourcesClosed, applying reused energy to power laser and ancillary plant operations
Fuel cycle (tritium)Produced offsiteBred onsite

The Laser Driven Fusion Integration Research and Science Test Facility (LD-FIRST) is a proposed blueprint for a proof-of-concept IFE facility that will test all the key IFE subsystems in an integrated fashion. A public-private partnership will likely be necessary to build the facility and will help the IFE community address the main subset of risks and the technological challenges of building a commercial plant.

Converging on a Solution

The team seeks to make IPM as accurate and comprehensive as possible by meeting with subject matter experts across the Laboratory to incorporate the latest research. “We’re trying to evolve the model so it has the same level of high detail across every single functional area to tell us where we can focus research and help us find optimized solutions that we could propose to industry,” says Nelson.

Computer scientist Claudio Santiago and his colleagues also modernized IPM by porting its framework from Microsoft Excel to Python in December 2024, making it compatible with AI, ML, design optimization, and HPC to further inform designs. “Once we think about all the forcing functions such as minimum shot yield and materials requirements pinning us in from every direction, we end up with an optimized solution space. As we sharpen the pencil more with these tools, that optimized solution box gets smaller until eventually we’ve converged on a point design,” says IFE lead systems engineer Justin Galbraith. Galbraith and his team’s point design is called the Laser Driven Fusion Integration Research and Science Test Facility, or LD-FIRST, a proof-of-concept physics demonstration facility for IFE. “That point design, we anticipate, will serve as the foundation for a future public-private partnership that would facilitate building and realizing a physical facility to focus the IFE community in pursuit of fusion power on the grid,” says Galbraith.

Livermore is leading the charge in IFE, helping the United States develop a technological roadmap, growing and coordinating science and technology efforts within the Laboratory, and fostering partnerships across the fusion industry, academia, and government.

Ma chaired DOE’s “Basic Research Needs for IFE” workshop and report in 2022 and co-chairs the subcommittee providing recommendations on the nation’s fusion activities through DOE’s Fusion Energy Sciences Advisory Committee. She and her team travel often to Washington, D.C., working with DOE and legislators to expand fusion energy research and advocacy in the nation. Livermore also leads a “Collaboratory” with other DOE national laboratories to connect research project leads and facilitate public-private partnerships. The Collaboratory has hosted multiple events with industry, and the Laboratory has partnered with three private companies who aim to design pilot IFE plants.

Meanwhile, Galbraith and other IFE leaders have served as technical advisors for engineering design teams at Texas A&M University and given them IFE-relevant problems to solve, including advanced chamber and blanket design. Galbraith is working with Nelson to develop the IFE plant design portion of a high-energy-density science summer school program, which Nelson is leading in 2025 at the University of California at San Diego, and they have developed IFE curriculum that has been deployed at six universities starting in spring 2025. “We’re hoping we can get a group of students really excited about fusion and start to build up the next generation of engineers and scientists that will make fusion a reality,” says Galbraith. The team has led IFE strategic planning exercises at the Laboratory, and Lawrence Livermore will stand up a new fusion institute—named “LIFT,” for Livermore Institute for Fusion Technology—a research and development center that will coordinate and centralize institutional fusion energy research.

Harnessing IFE will be a massive undertaking, but Livermore’s broad and deep expertise, facilities, and capabilities put the Laboratory in a unique position to lead and play an impactful role. “If we can set it up correctly, IFE will be a big piece of the Laboratory’s long-term vision,” says Ma. “IFE plays off of our history and all of our strengths, and it is critical for long-term national security.”

Economics-Watching: “Doing Nothing” Is Still Doing a Lot

[from the Federal Reserve Bank of Philadelphia, speech by Patrick T. Harker President and Chief Executive Officer at the National Association of Corporate Directors Webinar, Philadelphia, PA (Virtual)]

Good afternoon, everyone.

I appreciate that you’re all giving up part of the end of your workday for us to be together, if only virtually.

My thanks to my good friend, Rick Mroz, for that welcome and introduction.

I do believe we’re going to have a productive session. But just so you all know, as much as I enjoy speaking and providing my outlook, I enjoy a good conversation even more.

So, first, let’s take a few minutes so I can give you my perspective on where we are headed, and then I will be more than happy to take questions and hear what’s on your minds.

But before we get into any of that, I must begin with the standard Fed disclaimer: The views I express today are my own and do not necessarily reflect those of anyone else on the Federal Open Market Committee (FOMC) or in the Federal Reserve System.

Put simply, this is one of those times where the operative words are, “Pat said,” not “the Fed said.”

Now, to begin, I’m going to first address the two topics that I get asked about most often: interest rates and inflation. And I would guess they are the topics front and center in many of your minds as well.

After the FOMC’s last policy rate hike in July, I went on record with my view that, if economic and financial conditions evolved roughly as I expected they would, we could hold rates where they are. And I am pleased that, so far, economic and financial conditions are evolving as I expected, if not perhaps even a tad better.

Let’s look at the current dynamics. There is a steady, if slow, disinflation under way. Labor markets are coming into better balance. And, all the while, economic activity has remained resilient.

Given this, I remain today where I found myself after July’s meeting: Absent a stark turnabout in the data and in what I hear from contacts, I believe that we are at the point where we can hold rates where they are.

In barely more than a year, we increased the policy rate by more than 5 percentage points and to its highest level in more than two decades — 11 rate hikes in a span of 12 meetings prior to September. We not only did a lot, but we did it very fast.

We also turned around our balance sheet policy — and we will continue to tighten financial conditions by shrinking the balance sheet.

The workings of the economy cannot be rushed, and it will take some time for the full impact of the higher rates to be felt. In fact, I have heard a plea from countless contacts, asking to give them some time to absorb the work we have already done.

I agree with them. I am sure policy rates are restrictive, and, as long they remain so, we will steadily press down on inflation and bring markets into a better balance.

Holding rates steady will let monetary policy do its work. By doing nothing, we are still doing something. And I would argue we are doing quite a lot.

Headline PCE inflation remained elevated in August at 3.5 percent year over year, but it is down 3 percentage points from this time last year. About half of that drop is due to the volatile components of energy and food that, while basic necessities, they are typically excluded by economists in the so-called core inflation rate to give a more accurate assessment of the pace of disinflation and its likely path forward.

Well, core PCE inflation has also shown clear signs of progress, and the August monthly reading was its smallest month-over-month increase since 2020.

So, yes, a steady disinflation is under way, and I expect it to continue. My projection is that inflation will drop below 3 percent in 2024 and level out at our 2 percent target thereafter.

However, there can be challenges in assessing the trends in disinflation. For example, September’s CPI report came out modestly on the upside, driven by energy and housing.

Let me be clear about two things. First, we will not tolerate a reacceleration in prices. But second, I do not want to overreact to the normal month-to-month variability of prices. And for all the fancy techniques, the best way to separate a signal from noise remains to average data over several months. Of course, to do so, you need several months of data to start with, which, in turn, demands that, yes, we remain data-dependent but patient and cautious with the data.

Turning to the jobs picture, I do anticipate national unemployment to end the year at about 4 percent — just slightly above where we are now — and to increase slowly over the next year to peak at around 4.5 percent before heading back toward 4 percent in 2025. That is a rate in line with what economists call the natural rate of unemployment, or the theoretical level in which labor market conditions support stable inflation at 2 percent.

Now, that said, as you know, there are many factors that play into the calculation of the unemployment rate. For instance, we’ve seen recent months where, even as the economy added more jobs, the unemployment rate increased because more workers moved off the sidelines and back into the labor force. There are many other dynamics at play, too, such as technological changes or public policy issues, like child care or immigration, which directly impact employment.

And beyond the hard data, I also have to balance the soft data. For example, in my discussions with employers throughout the Third District, I hear that given how hard they’ve worked to find the workers they currently have, they are doing all they can to hold onto them.

So, to sum up the labor picture, let me say, simply, I do not expect mass layoffs.

do expect GDP gains to continue through the end of 2023, before pulling back slightly in 2024. But even as I foresee the rate of GDP growth moderating, I do not see it contracting. And, again, to put it simply, I do not anticipate a recession.

Look, this economy has been nothing if not unpredictable. It has proven itself unwilling to stick to traditional modeling and seems determined to not only bend some rules in one place, but to make up its own in another. However, as frustratingly unpredictable as it has been, it continues to move along.

And this has led me to the following thought: What has fundamentally changed in the economy from, say, 2018 or 2019? In 2018, inflation averaged 2 percent almost to the decimal point and was actually below target in 2019. Unemployment averaged below 4 percent for both years and was as low as 3.5 percent — both nationwide and in our respective states — while policy rates peaked below 2.5 percent.

Now, I’m not saying we’re going to be able to exactly replicate the prepandemic economy, but it is hard to find fundamental differences. Surely, I cannot and will not minimize the immense impacts of the pandemic on our lives and our families, nor the fact that for so many, the new normal still does not feel normal. From the cold lens of economics, I do not see underlying fundamental changes. I could also be wrong, and, trust me, that would not be the first time this economy has made me rethink some of the classic models. We just won’t know for sure until we have more data to look at over time.

And then, of course, there are the economic uncertainties — both national and global — against which we also must contend. The ongoing auto worker strike, among other labor actions. The restart of student loan payments. The potential of a government shutdown. Fast-changing events in response to the tragic attacks against Israel. Russia’s ongoing war against Ukraine. Each and every one deserves a close watch.

These are the broad economic signals we are picking up at the Philadelphia Fed, but I would note that the regional ones we follow are also pointing us forward.

First, while in the Philadelphia Fed’s most recent business outlook surveys, which survey manufacturing and nonmanufacturing firms in the Third District, month-over-month activity declined, the six-month outlooks for each remain optimistic for growth.

And we also publish a monthly summary metric of economic activity, the State Coincident Indexes. In New Jersey, the index is up slightly year over year through August, which shows generally positive conditions. However, the three-month number from June through August was down, and while both payroll employment and average hours worked in manufacturing increased during that time, so did the unemployment rate — though a good part of that increase can be explained as more residents moved back into the labor force.

And for those of you joining us from the western side of the Delaware River, Pennsylvania’s coincident index is up more than 4 percent year over year through August and 1.7 percent since June. Payroll employment was up, and the unemployment rate was down; however, the number of average hours worked in manufacturing decreased.

There are also promising signs in both states in terms of business formation. The number of applications, specifically, for high-propensity businesses — those expected to turn into firms with payroll — are remaining elevated compared with pre-pandemic levels. Again, a promising sign.

So, it is against this full backdrop that I have concluded that now is the time at which the policy rate can remain steady. But I can hear you ask: “How long will rates need to stay high.” Well, I simply cannot say at this moment. My forecasts are based on what we know as of late 2023. As time goes by, as adjustments are completed, and as we have more data and insights on the underlying trends, I may need to adjust my forecasts, and with them my time frames.

I can tell you three things about my views on future policy. First, I expect rates will need to stay high for a while.

Second, the data and what I hear from contacts and outreach will signal to me when the time comes to adjust policy either way. I really do not expect it, but if inflation were to rebound, I know I would not hesitate to support further rate increases as our objective to return inflation to target is, simply, not negotiable.

Third, I believe that a resolute, but patient, monetary policy stance will allow us to achieve the soft landing that we all wish for our economy.

Before I conclude and turn things over to Rick to kick off our Q&A, I do want to spend a moment on a topic that he and I recently discussed, and it’s something about which I know there is generally great interest: fintech. In fact, I understand there is discussion about NACD hosting a conference on fintech.

Well, last month, we at the Philadelphia Fed hosted our Seventh Annual Fintech Conference, which brought business and thought leaders together at the Bank for two days of real in-depth discussions. And I am extraordinarily proud of the fact that the Philadelphia Fed’s conference has emerged as one of the premier conferences on fintech, anywhere. Not that it’s a competition.

I had the pleasure of opening this year’s conference, which always puts a focus on shifts in the fintech landscape. Much of this year’s conference centered around developments in digital currencies and crypto — and, believe me, some of the discussions were a little, shall we say, “spirited.” However, my overarching point to attendees was the following: Regardless of one’s views, whether in favor of or against such currencies, our reality requires us to move from thinking in terms of “what if” to thinking about “what next.”

In many ways, we’re beyond the stage of thinking about crypto and digital currency and into the stage of having them as reality — just as AI has moved from being the stuff of science fiction to the stuff of everyday life. What is needed now is critical thinking about what is next. And we at the Federal Reserve, both here in Philadelphia and System-wide, are focused on being part of this discussion.

We are also focused on providing not just thought leadership but actionable leadership. For example, the Fed rolled out our new FedNow instant payment service platform in July. With FedNow, we will have a more nimble and responsive banking system.

To be sure, FedNow is not the first instant payment system — other systems, whether operated by individual banks or through third parties, have been operational for some time. But by allowing banks to interact with each other quickly and efficiently to ensure one customer’s payment becomes another’s deposit, we are fulfilling our role in providing a fair and equitable payment system.

Another area where the Fed is assuming a mantle of leadership is in quantum computing, or QC, which has the potential to revolutionize security and problem-solving methodologies throughout the banking and financial services industry. But that upside also comes with a real downside risk, should other not-so-friendly actors co-opt QC for their own purposes.

Right now, individual institutions and other central banks globally are expanding their own research in QC. But just as these institutions look to the Fed for economic leadership, so, too, are they looking to us for technological leadership. So, I am especially proud that this System-wide effort is being led from right here at the Philadelphia Fed.

I could go on and talk about fintech for much longer. After all, I’m actually an engineer more than I am an economist. But I know that Rick is interested in starting our conversation, and I am sure that many of you are ready to participate.

But one last thought on fintech — my answers today aren’t going to be generated by ChatGPT.

On that note, Rick, thanks for allowing me the time to set up our discussion, and let’s start with the Q&A.

[archived PDF of the above speech]

Education and “The Three-Body Problem”

The brilliant math-watcher, Ian Stewart, says of this classic physics problem, the Three-Body Problem:

Newton’s Law of Gravity runs into problems with three bodies (earth, moon, sun, say).

In particular, the gravitational interaction of a mere three bodies, assumed to obey Newton’s inverse square law of gravity, stumped the mathematical world for centuries.

It still does, if what you want is a nice formula for the orbits of those bodies. In fact, we now know that three-body dynamics is chaotic–so irregular that is has elements of randomness.

There is no tidy geometric characterization of three-body orbits, not even a formula in coordinate geometry.

Until the late nineteenth century, very little was known about the motion of three celestial bodies, even if one of them were so tiny that its mass could be ignored.

(Visions of Infinity: The Great Mathematical Problems, Ian Stewart, Basic Books, 2014, page 136)

Henri Poincaré, the great mathematician, wrestled with this with tremendous intricacy and ingenuity all his life:

Jules Henri Poincaré was a French mathematician, theoretical physicist, engineer, and philosopher of science. He is often described as a polymath, and in mathematics as “The Last Universalist,” since he excelled in all fields of the discipline as it existed during his lifetime.

Born: April 29, 1854, Nancy, France
Died: July 17, 1912, Paris, France.

We now think of applying in an evocative and not a rigorous mathematical way, the unexpected difficulties of the three-body problem to the n-body (i.e., more than three) problems of sociology or economics or history itself, and sense that social life is always multifactorial and not readily pin-downable, since “everything is causing everything else” and extracting mono-causal explanations must be elusive for all the planetary and Poincaré reasons and beyond.

This suggests to the student that novels are one attempt to say something about n-body human “orbits” based on “n-body” stances and “circumstances” with large amounts of randomness governing the untidy mess that dominates human affairs.

Words are deployed in novels and not numbers as in physics, but the “recalcitrance” of the world, social and physical, remains permanent.

Education and meta-intelligence would be more complete by seeing how the world, as someone put it, “won’t meet us halfway.” Remember Ian Stewart’s warning above:

“There is no tidy geometric characterization of three-body orbits…” and you sense that this must apply to human affairs even more deeply.