Can physicist Tammy Ma lead us to abundant clean energy?
The high point of Tammy Ma’s career happened while she was sleeping.
Early one December morning in 2022, scientists at the National Ignition Facility in Livermore, California, fired 192 lasers at a peppercorn-size fuel pellet suspended in a giant blue orb.
Almost 400 such shots are deployed each year to test materials under stress and further our understanding of the physics of nuclear weapons testing and astrophysical phenomena like supernovas. A few test the potential for developing a new supply of clean energy by replicating the processes that power the sun — Ma’s chief focus as director of the Livermore Institute for Fusion Technology.
The next morning, Ma’s phone lit up as she prepared to board a flight to Washington, D.C. Members of her staff told her all the signs of a new breakthrough were there: A gamma ray alarm had gone off; the fluorescent ceiling lights in the target bay went out; and the early diagnostics were convincing. The lasers had forced atoms to fuse and create what appeared to be a net energy gain, which would mark a historic milestone in the decades-long effort to produce commercial energy from fusion, the science that might one day provide abundant, carbon-free energy.
The scientists ran and reran the numbers for a week before the Livermore team confirmed the findings at a news conference. “We had been burned in the past. We have learned to be very, very careful,” said Ma in a recent interview. The taxpayer-funded facility had been dogged by failure, raising fears about its future financing.
“Our job as the national lab is to be the arbiter of truth,” she said, reflecting her natural caution even as she recalled her suppressed glee when she contacted her mother from the San Francisco airport that early-December day: “Mom, I think we got ignition!”
The older child of Chinese immigrants who viewed science as the route to their children’s success, Ma was raised to respect America’s academic enterprise. After school, her father, an electrical engineer, would load Ma and her younger brother into his old gray Camry and drive them over the hills from their home to Livermore to participate in STEM outreach events.
Not that she foresaw a career in fusion. She was more interested in aerospace engineering as a teenager and dreamed of becoming an astronaut. But during the summer between high school and her freshman year at the California Institute of Technology, Ma interned at Livermore, sitting in front of a computer for eight hours a day in a fruitless search for new planets somewhere between Saturn and Uranus. While there, she toured the unfinished NIF and felt a sense of awe standing below the 30-foot diameter spherical blue target chamber, which had to be lowered into place by cranes so the rest of the stadium-size NIF could be constructed around it.
“It would be so cool to do science on this scale,” Ma remembers thinking. “Big, team science.”
Twenty-five years later, Ma, 42, remains motivated by that kind of mission-driven research — tackling “the hardest scientific problems that humans can go after” — even as she remains acutely aware of the dangers of overpromising. The surging power demands of data centers, the need to reduce reliance on fossil fuels, the moral obligation to electrify the developing world, and the search for energy independence have captured public attention and investor interest.
“We’re in a hype cycle,” Ma said, resulting from a confluence of real technological advances, the application of artificial intelligence and what she describes as “crazy promises.” The once-esoteric field is now attracting tech bros, venture capitalists and philanthropists like Bill Gates. Private companies have sprung up from promising enterprises such as Commonwealth Fusion Systems, which is breaking ground for a magnet-powered rather than laser-powered fusion plant in Virginia, as well as fly-by-night start-ups. President Donald Trump has even entered the fray, striking a $6 billion deal between his media and technology group with the Google-backed fusion company TAE Technologies.
While the dream of producing abundant clean energy is compelling and the focus of her current work, Ma remains keenly aware of NIF’s core missions of supporting materials science and nuclear weapons stewardship by studying matter under extreme conditions, including testing the physics of hydrogen bombs without performing actual detonations.
“It’s about making sure the U.S. remains competitive,” said Ma, who is a strong believer in the deterrence that comes from demonstrating the country’s scientific prowess to potential foes. “Our work is open on purpose to show the world how good we are, so you had better believe our weapons will work.”
While some fusion researchers shy away from the term “nuclear” for fear of losing public support, Ma describes herself as belonging to “a different camp.”
“Fusion is a nuclear power,” Ma said, though more akin — in terms of risk — to nuclear medicine than nuclear fission with its challenges of highly radioactive waste disposal and the potential for a meltdown. “The onus is on us to communicate, not to be opaque.”
To that end, she travels frequently, appearing at high-level conferences and in elementary school classrooms. She has given a TED Talk; she advises governments; and she makes a priority of engaging with community groups. She is driven by an understanding that big team science aimed at solving the most difficult scientific problems will require an army of experts of all kinds, explains Arturo Dominguez, a plasma physicist at Princeton University who has collaborated with Ma on educational outreach programs.
All of which means that Ma spends little time in the lab these days. “I don’t know how to turn a screwdriver anymore,” she laughs.
Looking ahead, she sees a future in some form of science diplomacy, arming policymakers with scientific expertise, even as she remains committed to tackling the hardest scientific problems of our age.
“The challenges of harnessing fusion energy will be even more difficult than the process of getting to ignition,” Ma said, reflecting the soaring ambition and down-to-earth realism that have shaped her successes so far.
