Nuclear fusion reactions can be dramatically increased at low energies by surrounding materials, according to a recent discovery by scientists at UC Davis and Lawrence Berkeley National Laboratory that establishes an entirely new area of research called materials-driven fusion.
Researchers packed deuterium—a heavy form of hydrogen—into thin metal foils made of titanium and palladium using two different loading techniques. According to the study team, the goal was testing how host materials affect fusion by firing a beam of deuterium ions directly at the loaded foils across a range of energy levels and measuring how often fusion happened compared to open-space reactions.
Subatomic Shielding Drives Unexpected Fusion Plateaus
Standard physics theory predicts that fusion rates drop off sharply when collision energies fall below 2.5 kiloelectronvolts (keV). However, measurements showed an unexpected result where fusion rates leveled off into a plateau at lower energies, according to the research team.
In certain metal samples, fusion occurred about a quintillion times—a 1 followed by 18 zeroes—more often than in reactions without a host material. This jump in reaction rates comes down to the subatomic structure of the host metals, where electrons and tiny defects in the foil structure act like a shield around positively charged deuterium nuclei.
“The electrons and defects within the material might partially shield repulsive electrostatic forces between deuterium nuclei, making it easier for them to get close together and fuse,” the researchers explained in a press release.
Did you know? Standard physics theory predicts that fusion rates drop off sharply when collision energies fall below 2.5 kiloelectronvolts (keV).
Engineering Future Materials for Fusion and Neutron Generators
The work establishes a reliable, repeatable way to test how solid metals affect nuclear interactions, creating a fresh link between fusion science, materials science, and chemistry. Instead of designing materials just to survive harsh operational conditions, researchers might be able to design materials that boost the reaction in specific conditions, similar to the way catalysts speed up chemical processes.
“If we understand this effect better, it opens the door to engineering new materials that would affect the fusion rate under certain conditions,” said Arun Persaud, head of the Fusion Science & Ion Beam Technology group in Berkeley Lab’s Accelerator Technology & Applied Physics (ATAP) Division.
Persaud noted that future progress might enable more compact and efficient neutron generators with applications in cargo screening, planetary science, and medical therapy and imaging.
Predictive Modeling with DuctGPT in Extreme Environments
This discovery connects with work happening at Ames National Laboratory to better understand how materials handle nuclear operations. Scientists there are currently expanding an artificial intelligence tool called DuctGPT to improve predictions about how materials behave inside active fusion energy systems.
Running a fusion system subjects surrounding parts to harsh operational conditions, including intense heat, radiation, and mechanical stress. By adding new data and models to DuctGPT, researchers can better predict how different materials hold up under these extreme forces over time.
Frequently Asked Questions
What is materials-driven fusion?
Materials-driven fusion is a new area of research focusing on how surrounding host materials, such as titanium and palladium foils packed with deuterium, can dramatically increase nuclear fusion rates at low energies.
How do metal foils increase fusion rates?
Electrons and tiny defects inside the metal foil act like a shield, potentially reducing the repulsive electrostatic forces between positively charged deuterium nuclei and allowing them to get close enough to fuse more easily.
What are potential applications for this discovery?
According to Berkeley Lab researchers, future progress might enable more compact and efficient neutron generators used in medical therapy and imaging, planetary science, and cargo screening.
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