Lab Achieves Micro Scale Nuclear Fusion

Colorado State University scientists using a compact but powerful laser to heat arrays of ordered nanowires have demonstrated micro-scale nuclear fusion in the lab. They have achieved record-setting efficiency for the generation of neutrons – chargeless sub-atomic particles resulting from the fusion process. The process that powers the sun, happens when nuclear reactions between light elements produce heavier ones, is occurring at a smaller scale, in a lab.

Their work is detailed in an open paper published in Nature Communications, and is led by Jorge Rocca, University Distinguished Professor in electrical and computer engineering and physics. The paper’s first author is Alden Curtis, a CSU graduate student.

Laser-driven controlled fusion experiments are typically done at multi-hundred-million-dollar lasers housed in stadium-sized buildings. Such experiments are usually geared toward harnessing fusion for clean energy applications.

In contrast, Rocca’s team of students, research scientists and collaborators, work with an ultra fast, high-powered tabletop laser they built from scratch. They use their fast, pulsed laser to irradiate a target of invisible wires and instantly create extremely hot, dense plasmas – with conditions approaching those inside the sun. These plasmas drive fusion reactions, giving off helium and flashes of energetic neutrons.

In their Nature Communications experiment, the team produced a record number of neutrons per unit of laser energy – about 500 times better than experiments that use conventional flat targets from the same material. Their laser’s target was an array of nanowires made out of a material called deuterated polyethylene. The material is similar to the widely used polyethylene plastic, but its common hydrogen atoms are substituted by deuterium, a heavier kind of hydrogen atom.

The efforts were supported by intensive computer simulations conducted at the University of Dusseldorf (Germany), and at CSU.

Making fusion neutrons efficiently, at a small scale, could lead to advances in neutron-based imaging, and neutron probes to gain insight on the structure and properties of materials. The results also contribute to understanding interactions of ultra-intense laser light with matter.

Its interesting to see fusion being explored for neutron production instead of electrons for power. The situation noted the energy content of the neutrons while the energy of the electrons went unmentioned and perhaps not actually unmeasured. One does wonder if the experiment did in fact measure the all energy, because some if not a lot of the funding is from the U.S Air Force. One might think there is more here than is reported.

Of great note is that the target is an extremely innovative creation. With results that soar over those we’ve seen from the really huge National Ignition Facility, there is likely some intense thought being given to just what this idea and others might make a difference to the Ignition Facility’s work.

One has to think that someday soon something is going to crack and there will be a net power result from some group. It would have been nice to get the calculation on what the input and total energy output were at CSU. Or maybe its a secret.