Laser Assisted Fusion Without Confinement?
Written by Tim Lash, Focus Fusion Society Contributor. Edited by Ignas Galvelis, Supervising Director.
In March an international team of physicists reported on a novel approach to nuclear fusion. Foregoing the standard containment approaches, they propose using ultra-short bursts of lasers to nudge nuclei together. These photonic nudges could be used to provide the conditions for nuclei to overcome their electrostatic repulsion until the strong force could take over. Once nuclei are in close enough proximity the chance of fusion reaction becomes much more likely.
Scientists from Rice University, the University of Illinois at Urbana-Champaign and the University of Chile collaborated on a two dimensional simulation between deuterium and tritium. Authors Peter Wolynes of Rice, Martin Gruebele of Illinois and Illinois alumnus Eduardo Berrios of Chile ran a simulation demonstrating specially tuned femtosecond laser pulses could place nuclei in the required proximity. Their work stems from a background in femtochemistry, in which femtosecond-long laser flashes trigger chemical reactions.
The simulation studied the behavior of deuterium and tritium when subjected to carefully shaped 5-femtosecond pulses of near-infrared laser light. The modeled laser pulses were able to bring the nuclei to within a small fraction of an angstrom. One drawback to this line of research is that the current fusion model produces its energy as neutrons. High energy neutrons are not easily contained and can jeopardize reactor components turning surrounding material radioactive. That is one reason why Lawrenceville Plasma Physics research pursues aneutronic pB11 fusion reactions.
The researchers constrained their simulation to two dimensions to simplify the iterative modeling process. Likewise, electrons were also unaccounted for during this exercise. This gives future studies plenty of ground to explore. Wolynes and Gruebele are more accustomed to studying protein folding, cell dynamics, nano-structure microscopy and fish swimming behavior. However, they have long wondered whether their laser techniques could be applied to fusion. They hope these simulation results are compelling enough to garner the attention of other researchers, or that they themselves may be able to devote additional time to conduct further studies along these lines.