Nuclear fusion remains to be the dream for our planet’s power generation, promising a zero-emissions power source that can grant us so much energy that people think of it as revolutionizing life on Earth.
But, for now, that’s exactly what it remains to be—a dream. Ultimately, the current level of refinement of our nuclear fusion technologies require more energy to start than it is capable of releasing, meaning we have quite some ways to go before we can achieve true, sustainable nuclear fusion.
That doesn’t mean our brightest minds have stopped trying, though; they are still at work trying to improve our understanding of what ultimately powers stars like our own Sun, to try and bring their machinery down to Earth and assist our society. Some earlier attempts have already made leaps and bounds in improving efficiencies for these setups, like an earlier report from August this year which made use of 192 lasers to heat a hydrogen fuel source.
Now, new research into nuclear fusion methodologies was published in the Philosophical Transaction of the Royal Society A last year. In it, scientists and engineers working for the United States’ Naval Research Laboratory (NRL) are busy chasing after the prospect of making nuclear fusion technology commercially viable—and they are planning on using argon fluoride (ArF) lasers to do it.
The new ArF laser uses the principle of inertial confinement fusion (ICF). In ICF, a fusion fuel source—in this case a pea-sized bead of hydrogen isotopes like deuterium and tritium—is heated by a plethora of lasers, rapidly heating the fuel source while confining it under immense pressures. The goal is that the fuel source is both heated and compressed enough that nuclear fusion begins and keeps going.
In the study, researchers attempt to approach heating the fusion fuel in excess of 100 million °C (180 million °F), and while under sufficient pressure. In doing so, the team hopes to initiate the actual nuclear fusion reaction while generating enough excess energy to sustain the reaction, keeping it going and making the whole system self-sufficient while generating an energy surplus for the power grid. As expected, though, this feat is absolutely not easy to do while chasing the goal of also making the whole thing economical.
Now, the ArF laser is considered a wide-bandwidth ultraviolet laser, and is designed to efficiently transfer energy from the laser itself to the fuel bead. Radiation hydrodynamics simulations by the NRL have already displayed it possibly achieving 16% efficiency while scaling up its performance by 100 times; this stands in comparison to the 12% efficiency that is currently being achieved by earlier laser technology using krypton fluoride (KrF) lasers.
The NRL hopes to achieve their goals for the study in the future by using a three-stage approach, which includes a) establishing the science and technology of the laser, b) producing a full-scale ArF laser as a concept, and c) creating a full-scale implosion facility with some 20 or 30 lasers for full testing.
While the improvements seem trivial at first, these improvements are considered landmarks in the quest for limitless, zero-emissions renewable energy. Thus, the efficiency improvements introduced by ArF lasers can be further developed into potential cost-cutting measures for future nuclear fusion power plants. Despite these, the path ahead remains long and winding for this technology which appears to still be in its infancy.
In the words of NRL Ph.D. research physicist Dr. Steve Obenschain: “The advantages could facilitate the development of modest size, less expensive fusion power plant modules operating at laser energies less than one megajoule. That would drastically change the existing view on laser fusion energy being too expensive and power plants being too large.”
References
- Argon fluoride laser could lead to practical fusion reactors. (2021, October 24). New Atlas. https://newatlas.com/science/argon-fluoride-laser-practical-fusion-reactor/
- Lehecka, T., Bodner, S., Deniz, A. V., Mostovych, A. N., Obenschain, S. P., Pawley, C. J., & Pronko, M. S. (1991). The NIKE KrF laser fusion facility. Journal of Fusion Energy, 10(4), 301–303. https://doi.org/10.1007/BF01052128
- Obenschain, S. P., Schmitt, A. J., Bates, J. W., Wolford, M. F., Myers, M. C., McGeoch, M. W., Karasik, M., & Weaver, J. L. (2020). Direct drive with the argon fluoride laser as a path to high fusion gain with sub-megajoule laser energy. Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, 378(2184), 20200031. https://doi.org/10.1098/rsta.2020.0031
