Improving fusion performance is tricky business. Tiny deviations from perfect spherical symmetry can lead to significant degradation of inertial confinement fusion (ICF) implosions. But tracking down those defects is devilishly difficult. That’s exactly the problem Dan Casey is working to solve. “I came here to be on the front lines, and I am richly rewarded with fascinating and challenging problems every day,” says Dan. “I often feel like my job is to solve experimental puzzles, and I love puzzles!”
Dan is a physicist studying the properties and performance of ICF implosions at the National Ignition Facility. He works with a team that focuses on understanding 3D areal-density asymmetries that can damage and ultimately impact implosion quality. Dan is also the experimental co-lead for a campaign to test the role of hydrodynamic instabilities in degrading implosion compression, a key metric to achieving ignition and high gain. His work led to his 2019 selection for the prestigious Presidential Early Career Award for Science and Engineers, an honor he described as “extraordinary and humbling.”
“One of the things I have really come to value about Livermore is the people,” he says. “The facilities are second to none, but the Lab’s most precious resources are the talented and brilliant people attracted to the important work we do here.”
Dan holds a Ph.D. in nuclear science and engineering from the Massachusetts Institute of Technology and was one of the first graduates of the NIF‒MIT Ph.D. Thesis Program.
Dayne Fratanduono has designed and executed experiments on leading high energy density (HED) research facilities including NIF, Sandia’s Z Machine, the OMEGA Laser Facility at the University of Rochester and the Advanced Photon Source at Argonne National Laboratory. As an expert in condensed matter physics, Dayne has observed that valuable contributions can be made as early as the postdoctoral research career level. “LLNL’s postdocs play a unique and important role bearing new discoveries in the quest for scientific truth and knowledge within HED science,” he says.
In an assignment with the National Nuclear Security Administration in Washington, D.C., Dayne provided technical and advisory expertise to federal program managers in the areas of HED physics, materials science and advanced light source strategies. After returning to LLNL, he served as co-program lead for Condensed Matter Physics within the Weapon Physics and Design Program. In this role, Dayne and team members explored experimental platforms and diagnostic probes to measure properties of stockpile materials.
Today, Dayne serves as NIF’s deputy director for capabilities, where he focuses on expanding LLNL’s ability to support fusion science research, while also supporting the stockpile stewardship mission.
Dayne holds a Ph.D. and an M.S. in mechanical engineering from the University of Rochester and a B.S. in physics and a B.S. in mechanical engineering, both from Clarkson University.
No one anticipated how Kelli Humbird’s summer internship at Lawrence Livermore would fuel her doctoral research and future career. While an intern with the Strategic Deterrence team, Kelli trained a machine learning model to interpolate between tens of thousands of Trinity supercomputer data points generated from nine parameters like various asymmetries, drive multipliers and gas-fill densities that affect the quality of inertial confinement fusion implosions. Kelli’s work evolved into a DOE-funded Laboratory Directed Research and Development project, and she became a Livermore Graduate Scholar while completing her Ph.D.
Kelli views her internship work as a “happy accident.” She says, “I was at the right place at the right time and given the right dataset. None of us were expecting a summer project to turn into something this big.” Now a design physicist at Livermore, she continues to apply machine learning tools to traditional weapons physics models. Kelli is also a member of the Global Security Directorate’s Nuclear Forensics Group’s emergency response team and works on projects that build machine learning tools for stockpile certification applications and for modeling the spread of COVID-19.
Kelli received her Ph.D., M.S. and B.S. in nuclear engineering, as well as a B.S. in physics, from Texas A&M University.
For an undergraduate student in nuclear engineering and radiological sciences, a summer internship at Lawrence Livermore National Laboratory was something Annie couldn’t pass up. “I was immediately drawn to ‘the big laser project’ and intrigued by the idea of a grand scientific challenge,” says Annie.
Annie returned to the Lab as a graduate scholar and then a Lawrence postdoctoral fellow. Today, she works in the Design Physics Division, designing and simulating inertial confinement fusion (ICF) experiments fielded at the National Ignition Facility (NIF) and is a team lead within the ICF program. Annie was the lead designer for the recent ICF experiments that achieved fusion ignition.
“The science that can be achieved in my field with the Lab’s available resources — hardware, technology and expertise — is unsurpassed and keeps me excited and challenged. Also, the close relationships that I’ve formed at the Laboratory and working with those people to solve difficult problems keeps me engaged,” she says.
With all her work responsibilities, Annie has more at home, where she’s raising three young children. “I’m proof that you can be a powerful leader of campaigns in groundbreaking science and have a work–life balance. Multidisciplinary teams benefit from having diversity, and people who think differently all contribute uniquely to solving problems. Women in science are no exception.”
Annie has a Ph.D. in nuclear engineering and plasma physics and a M.S. in nuclear engineering from the University of California, Berkeley, and a B.S. in nuclear engineering and radiological sciences from the University of Michigan. Annie was selected as a fellow of the American Physical Society in 2022, and was named to TIME’s annual list of the 100 most influential people in the world in 2023.
Sabrina started studying physics at the Julius-Maximilians-University Würzburg, Germany, in 2000. After three years she transferred to the University of Texas at Austin and received a M.A. in physics. In 2009 she received a Ph.D. in plasma physics from Imperial College London, UK. Her thesis work studied electron acceleration mechanisms in relativistic laser-plasma interactions.
After finishing her Ph.D., Sabrina worked as a research associate in the Plasma Physics Group at Imperial College London. In February 2011, she joined the HED Shock Physics Group at LLNL as a postdoc, where her research included dilation x-ray imaging. She has since been working on x-ray detectors for the National Ignition Facility (NIF) that can take images of implosions with unprecedented temporal resolution.
Sabrina became a group leader in the Physics division in 2018. She is the physics lead of the dynamic x-ray detector group for NIF and works closely with engineering and operations. She also regularly runs NIF shots for inertial confinement fusion (ICF) and high energy density campaigns.
Derek Mariscal is the High-Repetition-Rate (HRR) High Energy Density (HED) Science group leader and an experimental physicist within the National Ignition Facility (NIF) Advanced Photon Technologies HED Science team at Lawrence Livermore National Lab. He received his bachelor’s degree in physics at California State University, Stanislaus in 2008 before earning his graduate degree in engineering physics from the University of California at San Diego in 2015. Since arriving at LLNL in 2016, Derek has conducted experimental campaigns at facilities such as Jupiter Laser Facility, Omega EP, NIF, NIF-ARC and LaserNetUS. These experiments explore a diverse range of topics, including the impact of asymmetries and ice-ablator mix on ICF performance as well as short-pulse high-intensity laser-driven X-ray and MeV particle sources. The HRR HED Science group is working to develop intelligently-operated high repetition rate experiments by creating new HRR-capable diagnostics for laser-solid interactions, integrating machine learning for diagnostic analysis and building AI-driven platforms that merge simulations and experiments at HRR for accelerated scientific discovery.
Achieving Fusion Ignition
For more than 60 years, our researchers and colleagues worked to achieve fusion ignition, one of science’s most challenging goals. An experiment on Dec. 5, 2022, passed this historic milestone, opening new vistas of HED science, enabling access to regimes even more relevant for future stockpile stewardship and helping to create the groundwork to a path for fusion energy.
Specialized Diagnostics for Extreme Experiments
Grasping the extreme physics happening during HED experiments requires some of the most sophisticated measuring instruments ever made. Our highly specialized diagnostics operate in timescales of nanoseconds and detect interactions below the submicron level, often under intense bombardment of both particle and electromagnetic radiation. Diagnostics include streak cameras, neutron detectors, x-ray imaging and spectroscopy and the Advanced Radiographic Capability, the world’s most energetic short-pulse laser, located at NIF.
Experimental Data Inform Weapon-Simulation Codes
NIF is the only facility that can perform controlled, experimental studies of thermonuclear burn — the phenomenon that gives rise to the immense energy of modern nuclear weapons — providing unprecedented experimental access to the physics of nuclear weapons. The experimental data complement testing at other Livermore and partner experimental facilities, help to inform and validate sophisticated, 3D weapons-simulation computer codes and offer a fuller understanding of important weapon physics.
EBIT
Electron Beam Ion Trap Facility
The Electron Beam Ion Trap (EBIT) facility is home to a suite of x-ray and UV diagnostics, including high-resolution crystal and quantum calorimeter spectrometers used to measure photon emission with energies from below 100 eV to above 100 keV.
HEDS
High Energy Density Science Center
The High Energy Density Science (HEDS) Center facilitates opportunities for scientists and engineers to access world-class experimental facilities and engage in collaborative explorations of matter and energy under extreme conditions.
JLF
Jupiter Laser Facility
The Jupiter Laser Facility (JLF) delivers leading-edge science and supports the high energy density science research community with access to high-energy and high-power laser platforms.
NIF
National Ignition Facility
The National Ignition Facility (NIF) is the world’s largest and highest-energy laser system. Our unique energy and power enable cutting-edge research to help keep the U.S. stockpile safe and secure, explore new frontiers of science and lay the groundwork for a clean, sustainable source of energy.
SSI
Space Science Institute
The Space Science Institute’s (SSI) multidisciplinary teams address key questions in astrophysics and planetary science by analyzing, modeling and interpreting data obtained by existing observatories. We also analyze extraterrestrial materials on-site and develop technology and instrumentation for future observatories.
