Aug 18, 2023

Professor uses plasma rays to cool onboard electronics for US Air Force

Tom Cogill/UVA

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Researchers at the University of Virginia have figured out a way to cool down high-end electronics in military aircraft using plasma rays. The team led by Patrick Hopkins, a professor of mechanical and aerospace engineering at the university is turning science fiction into reality with its work, a press release said.

With increasing advancements in technology, military equipment is also studded with high-end electronics. Navies around the world are using water in their cooling systems while dense air helps cool the equipment rapidly on Earth.

For the Air Force, however, this has been a challenge due to the thin air it operates in. The upper layers of the atmosphere do not have a lot of air to facilitate cooling and aircraft cannot carry the extra weight of coolants onboard. Hopkins' team has found a lightweight and practical solution to the problem and that is the use of plasma.

Plasma, the fourth state of matter, is created when gases are energized. In this state, the electrons of the gaseous element leave their nuclear orbits and the matter can release photons, ions, or even electrons in a flow. These can be visualized in the form of a ray or a bolt of lightning.

A few years ago, Hopkins and his collaborator at the US Navy Research Laboratory, Scott Walton, made a surprising discovery. When they fired a purple jet of plasma created using helium on a gold-plated surface, they found that it cooled the object first before heating it up. This phenomenon has never been observed before and the researchers had to repeat their experiments on multiple occasions to confirm that their observations were indeed correct.

After their multiple observations, the researchers determined that the cooling was likely the result of blasting off of an ultra-thin surface layer of water and carbon molecules that was hard to see but existed on the surface of the object. Much like perspiration on our skin that uses energy from our body to evaporate and cool the body, this layer of molecules uses energy from the plasma to cool the object.

Tom Cogill/UVA

Hopkins envisions this instant cooling could be deployed in aircraft where a robotic arm could swing into action over areas where temperatures spike and instantly cool them with short bursts of plasma rays. This would be a major improvement over the "cold plate" that is currently used to take heat away from the electronics in air and space applications.

The US Air Force likes the concept and has awarded Hopkin's team at Experiments and Simulations in Thermal Engineering (ExSITE) lab a grant of $750,000 over three years to take it forward. Furthermore, the team will also build a prototype device through their spinout company, Laser Thermal.

The research findings were published in the journal ACS Nano.


The coupled interactions among the fundamental carriers of charge, heat, and electromagnetic fields at interfaces and boundaries give rise to energetic processes that enable a wide array of technologies. The energy transduction among these coupled carriers results in thermal dissipation at these surfaces, often quantified by the thermal boundary resistance, thus driving the functionalities of the modern nanotechnologies that are continuing to provide transformational benefits in computing, communication, health care, clean energy, power recycling, sensing, and manufacturing, to name a few. It is the purpose of this Review to summarize recent works that have been reported on ultrafast and nanoscale energy transduction and heat transfer mechanisms across interfaces when different thermal carriers couple near or across interfaces. We review coupled heat transfer mechanisms at interfaces of solids, liquids, gasses, and plasmas that drive the resulting interfacial heat transfer and temperature gradients due to energy and momentum coupling among various combinations of electrons, vibrons, photons, polaritons (plasmon polaritons and phonon polaritons), and molecules. These interfacial thermal transport processes with coupled energy carriers involve relatively recent research, and thus, several opportunities exist to further develop these nascent fields, which we comment on throughout the course of this Review.