SLAC Researchers Pioneer X-Ray Techniques to Perfect Fusion Fuel Targets
- MM24 News Desk
- 3 days ago
- 3 min read
SLAC National Accelerator Laboratory scientists are developing groundbreaking experimental methods to create the ideal fusion fuel target – a perfectly symmetrical capsule that can withstand temperatures hotter than the Sun and pressures exceeding Jupiter's core. In four recent studies using the lab's Linac Coherent Light Source (LCLS), early career researchers have established new frameworks for testing 3D-printed foam targets that could ultimately enable inertial fusion energy (IFE) power plants.
The challenge is monumental. Future fusion power plants will need to consume an estimated 10 fuel capsules every second, each no larger than a pea but perfectly engineered to compress symmetrically when hit by powerful lasers. "At SLAC, we're inventing new ways to study these fusion fuel targets and their potential behavior under the extreme conditions of a fusion power plant," said Arianna Gleason, SLAC staff scientist and deputy director of SLAC's High Energy Density Science (HEDS) division. The research is part of the Department of Energy's IFE-STAR program's RISE Hub.
The four studies, all published in Physics of Plasmas and led by emerging scientists, address different aspects of target performance. One critical question involves temperature measurement during the earliest laser interactions. Willow Martin, PhD candidate at Stanford University and member of SLAC's HEDS Division, led a team that laser-heated carbon samples at the Matter in Extreme Conditions (MEC) instrument.
"By bringing together two X-ray diagnostic techniques – Thomson scattering and fluorescence spectroscopy – we were able to cross reference our temperature measurements and build up confidence in our results," Martin explained. This novel approach provides crucial data on when materials transition from solid to plasma.
Another study focused on shockwave behavior through innovative materials. The team tested 3D-printed TPP (two-photon polymerization) foams against conventional aerogel foams, imaging them with ultrashort X-ray pulses as shockwaves comparable to fusion reactions traveled through them.
"As physicists, we want to work with idealized geometries – targets with perfect symmetry and zero imperfections – but reality gets in the way," said Claudia Parisuaña Barranca, graduate student at Stanford University and member of SLAC's HEDS Division. These real-world measurements, reported in the studies, help validate computer simulations that predict target performance.
Imperfections at microscopic scales can derail entire fusion reactions. Levi Hancock, undergraduate student at Brigham Young University and former Science Undergraduate Laboratory Internships student with SLAC's HEDS Division, led research imaging TPP foams with extraordinary precision.
Using ptycho-tomography at LCLS's X-ray Pump Probe (XPP) instrument, his team built detailed 2D and 3D reconstructions of foam pillars just 10 microns wide. "Given the low scattering, getting any 2D reconstructions at all felt like a miracle," Hancock noted, but the resulting images provided valuable data for improving fusion simulations.
The fourth study addressed perhaps the most persistent problem: tiny voids in capsule materials that sap energy from reactions. Daniel Hodge, graduate student at BYU, and his team deliberately created voids in samples, then blasted them with laser-driven shockwaves while tracking how these imperfections affected compression. "If we can fully understand the physics of void collapse in ablator materials by performing real experiments and comparing those results with simulations, then we can learn how to better design the targets," Hodge stated.
What drives these researchers through technical challenges and noisy data? For Martin, it's "contributing to a technology that could be so revolutionary for human society." For Hancock, the inspiration came when "the NIF [National Ignition Facility] announced that it had achieved ignition. That's when I decided I wanted to do fusion research." Their work represents both the present and future of fusion energy development, establishing experimental techniques that will guide target design for years to come.
Comments