“Achieving the necessary conditions for ignition has been a long-standing goal for all inertial confinement fusion research and opens access to a new experimental regime where alpha particle self-heating overcomes all cooling mechanisms of the fusion plasma”.
The documents describe the August 2021 results that made the breakthrough possible.
The laboratory conducted experiments in the “burning plasma” regime for the first time, which set the stage for the record shot. Alex Zylstra, LLNL physicist, principal experimentalist and first author of the experimental paper Physical Review E, noted in 2020 and early 2021.
“Based on this design, we made several improvements to get to the August 8, 2021 firing,” he said. “Improvements in the physical design and quality of the objective contributed to the success of the August capture, which is discussed in the articles in Physical Review E.”
Close up of atomic particle background science 3D illustration.
This experiment was then modified to include an improved goal design.
“Reducing travel time with more efficient hohlraums compared to previous experiments was key to moving between the ignition and burning plasma regimes,” said LLNL physicist Annie Kritcher, lead designer and first author of the Design article Physical Review E.
“The other major changes were improved capsule quality and a smaller fuel filler tube.”
Since its success last August, researchers have been trying to recreate the record-breaking performance to understand its experimental sensitivities.
“Many variables can affect each experiment,” Kritcher said. “The 192 laser beams do not perform exactly the same from shot to shot, the quality of the targets varies, and the ice layer grows with a different roughness on each target. These experiments provided an opportunity to test and understand the variability inherent in this new sensitive experimental regime”.