Record-setting nuclear fusion achieved on microscale using laser
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Researchers at Colorado State University have achieved record-smashing nuclear fusion on a microscopic scale using a simple tabletop laser to heat nanowires.
Nuclear fusion is a process in which atoms collide at high speed, overcoming the forces holding them apart, and fuse together to form heavier atoms. Through this process, a colossal amount of energy is released. This process powers our Sun and every other star.
Fusion can be driven by lasers on a much smaller scale; this type of fusion is typically carried out in enormous facilities with equipment costing hundreds of millions of dollars. However, researchers based at Colorado State University were able to achieve small-scale fusion using a tabletop laser that they built from scratch.
Using this modest set-up, the researchers set a new record for efficiency for the generation of neutrons (particles resulting from the process of fusion).
The researchers applied a highly compact and powerful laser to arrays of nanowires made out of deuterated polyethylene: a material similar to ordinary polyethylene plastic. This instantly generated hot, dense plasma, mimicking extreme solar conditions which drive fusion, producing helium and flashes of high-energy neutrons. In terms of neutrons produced per unit of laser energy, this was approximately 500 times more efficient than similar experiments which used conventional flat nanowire targets.
According to the Colorado State University team, generating fusion neutrons efficiently at this scale could be invaluable to research in the future, contributing to neutron-based imaging and neutron probes, which can be used to investigate the properties of materials.
Civil nuclear reactors use a different nuclear process – nuclear fission – whereby larger atoms are broken apart into smaller ones, releasing energy. Harnessing nuclear fusion on a larger scale could result in the generation of energy through a renewable process, which leaves behind no troublesome waste as nuclear fission does. However, the conditions under which nuclear fusion can occur are so extreme that they are not yet sustainable.
Earlier this month, Massachusetts Institute of Technology researchers announced that nuclear fusion could be deployed to power our homes and provide another alternative to fossil fuels within just 15 years.
This lowered estimate (nuclear fusion is always described as 30 or 50 years away) is due to confidence in a major new project, Sparc, which will use high-temperature superconductors to produce extremely powerful magnets in the world’s first fusion reactor which could generate more energy than it consumes.