0727 GMT October 19, 2019
It's also happening — at a smaller scale — in a Colorado State University (CSU) laboratory, according to sciencedaily.com.
Using a compact but powerful laser to heat arrays of ordered nanowires, CSU scientists and collaborators 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.
Their work was detailed in a 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.