Proponents of inertial fusion energy celebrated in December 2022, when researchers at the National Ignition Facility at Lawrence Livermore National Laboratory achieved fusion ignition by subjecting a carefully crafted diamond cryogenic sphere containing frozen deuterium-tritium fuel to NIF’s laser energy. NIF has yet to repeat the feat, in part because that facility was not designed to produce fusion energy, and ignition requires near-perfect targets. For inertial fusion energy to serve as a reliable power source, it will require swift, reliable, and economic target production.
Researchers at the University of Rochester’s Laboratory for Laser Energetics (LLE) announced on July 10 that they had “for the first time experimentally demonstrated a method called dynamic shell formation, which may help achieve the goal of creating a fusion power plant.” The researchers, including Igor Igumenshchev, a senior scientist at LLE, and Valeri Goncharov, a distinguished scientist and theory division director at LLE and an assistant professor (research) in the Department of Mechanical Engineering, published their findings in a paper published on July 7 in Physical Review Letters.
Keeping it liquid: The dynamic shell formation method tested at Rochester does not require freezing. Instead, a liquid droplet of deuterium and tritium is injected into a foam capsule. “When bombarded by laser pulses, the capsule develops into a spherical shell, then implodes and collapses, resulting in ignition,” according to the university’s press release.
Goncharov first described dynamic shell formation in a 2020 paper. The researchers’ recent attempt to prove the feasibility of the technique was a “scaled-down, proof-of-principle experiment” supported by the National Nuclear Security Administration using LLE’s OMEGA laser to shape a sphere of plastic foam with the same density as deuterium-tritium liquid fuel into a shell.
“This experiment has demonstrated feasibility of an innovative target concept suitable for affordable, mass production for inertial fusion energy,” Igumenshchev said.
Generating fusion energy using a scaled-up version of the dynamic shell formation technique would require lasers with longer and more energetic pulses. “Combining this target concept with a highly efficient laser system that is currently under development at LLE will provide a very attractive path to fusion energy,” Igumenshchev said.
Milestone pilot participation: The University of Rochester announced June 2 that LLE is partnering with Xcimer Energy, one of the two inertial fusion developers selected by the Department of Energy for the public-private Milestone-Based Fusion Development Program. LLE will “provide Xcimer with expertise in [inertial confinement fusion] implosion physics and design, as well as expertise on tritium,” and will design the tritium handling infrastructure for Xcimer’s inertial fusion energy research.
According to the University of Rochester, other institutions collaborating with Xcimer include the Naval Research Laboratory, Lawrence Livermore National Laboratory, Los Alamos National Laboratory, General Atomics, Westinghouse Electric Company, Oak Ridge National Laboratory, Savannah River National Laboratory, and the Massachusetts Institute of Technology.