Historic fusion ignition in a lab experiment confirmed
Lawrence Livermore National Laboratory has published an extensive paper confirming the validity of its 2022 fusion experiment where multiple lasers focused on a sphere of deuterium and tritium to achieve the first fusion ignition in a laboratory.
Creating nuclear fusion is relatively easy to produce. All you need are the conditions that place hydrogen isotope ions under the right conditions of heat and pressure to cause them to fuse into helium. In fact, it's so easy that it was the centerpiece of a General Electric exhibit that ran for 10 hours a day at the 1964 World's Fair.
The tricky bit is to achieve nuclear fusion while getting more energy out than you put in, which is called fusion ignition. Until December 5, 2022, this had only been accomplished on Earth inside a hydrogen bomb.
On that day at the Lawrence Livermore facility, 192 laser beams focused on a deuterium/tritium cryogenic target, delivering 2.05 megajoules (MJ) of ultraviolet light. The target fused and generated 3.15 MJ of energy output.
In other words, fusion ignition.
Since then, the team of over 1,370 researchers from 44 international institutions who contributed to the project over decades has worked to verify and document the results of that experiment. The newly released peer-reviewed paper reveals how the target gain of 1.5 times was achieved and traces the progress of the experiment back to its origin in 1972, as a proposal by LLNL Director John Nuckolls and his colleagues, as well as the challenges faced in achieving ignition.
According to the laboratory, the primary purpose of the laser experiment was to simulate the fusion reaction found inside a nuclear weapon in order to ascertain the reliability of the US nuclear stockpile without resorting to nuclear testing.
However, the results could also have applications in designing future fusion power plants, which could provide the world with limitless clean energy. This would not be directly because, though fusion ignition was achieved, the lasers required 100 times the energy to power them as was produced by the reaction.
"The NIF laser architecture and target configuration was chosen to give the highest probability for fusion ignition for research purposes and was not optimized to produce net energy for fusion energy applications,” said the researchers. "Inertial fusion energy applications requiring advancements to the underlying scheme require further development, such as laser energy usage, shot rate, target robustness, higher fuel compression levels, and cost."
The paper was published in Physical Review Letters.