Laser OMEGA. Credit: University of Rochester/J. Adam window.
In December 2022, they achieved a significant success at the US National Ignition Facility, which is part of the Lawrence Livermore National Laboratory in California. After a total of about 60 years of effort, they managed to use a system of 192 high-energy lasers to hit a fuel pellet with deuterium and tritium, causing an implosion and ignition of inertial-sustained fusion (inertial fusion ignition reaction).
It was undoubtedly a success, moreover, long desired. At the same time, it is clear that there is still a lot of work to be done before the practical use of fusion energy. For now, it is possible to continuously improve existing technologies and look for new ideas. This is exactly what the team led by Igor Igumenshchev from the American University of Rochester, New York State, did.
Laboratory for Laser Energetics. Kredit: University of Rochester.
They solved one of the relatively fundamental obstacles that plagues fusion engineers today – how to produce fuel pellets, needed to operate a fusion reactor of the above type. These days, these pellets are very complicated and expensive to produce. The manufacturing process involves using liquid helium to freeze deuterium and tritium to a temperature of 11 K above absolute zero. Then this material in the form of layers is used to produce pellets.
But this procedure is only good for laboratories where the fusion reactor is being developed and where they don’t care much about spending. For the practical operation of a fusion reactor, which would swallow a lot of fuel pellets every day, such a production procedure is very unsuitable.
logo. Credit: University of Rochester.
Therefore, the University of Rochester team has been working since 2020 on a technology that would allow the production of fuel pellets directly in the fusion device, using the high-energy lasers of the fusion reactor. In such a case, the shot of the fusion system of lasers would actually create a fuel pellet before implosion and ignition of the fusion.
Igumenshchev and colleagues did not use a solid fuel pellet. Instead, they injected deuterium and tritium into a foam capsule and placed it in the focus of fire from fusion lasers. Firing the lasers first causes the foam capsule to collapse into a sphere of deuterium and tritium whose density is the same as the fuel used today for this type of fusion. Then it implodes and the fusion ignites.
At the moment, the new type of fuel pellet processing is just an experimental process that has been verified at the Laboratory for Laser Energetics at the University of Rochester, where OMEGA, one of the most powerful lasers in the world, works. However, the researchers believe it could become a viable process for creating fuel pellets for this type of fusion.
Video: Laboratory for Laser Energetics, University of Rochester
Literature
Physical Review Letters 131: 015102.
2023-07-15 16:19:51
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