How nuclear fusion study helps cut turbulence, boost plasma thruster power

Scientists at the Centre for Energy, Environmental and Technological Research (CIEMAT) and the Plasma & Space Propulsion team at Universidad Carlos III de Madrid (UC3M) may seem to have little in common in terms of research interests, but the groups have found a problem that they can work together to solve – fusion plasma turbulence.

Plasma thrusters have been used in space exploration for decades now and are a reliable way to generate high exhaust speeds when compared to chemical fuel. Electric and magnetic fields can be used to accelerate charged particles or ionized gas through a small exhaust, generating soft-looking plasma thrust and steering satellites in their orbits.

The plasma generated isn’t very different from the one used in fusion nuclear reactors, which operate at temperatures as high as 150 million degrees. The plasma generates conditions for atomic nuclei to fuse and produce large amounts of energy.

However, the troubles faced by the fusion energy industry, such as plasma wall contact and turbulence, are also faced in plasma thrusters . This is where the two research groups working in seemingly different research areas can collaborate and gain from each other’s work.

Not that straightforward

“Even though we both work on plasmas, our technical terminology and our ways of looking at things are quite different,” explained Jaume Navarro, a researcher at UC3M, which hosts one of the biggest plasma propulsion research groups in Europe. “Once we had brought each other up to speed, we understood each other’s language and what challenges we have in common.”

Navarro collaborated with Carlos Hidalgo at CIEMAT, who helped transfer technical know-how about diagnostic tools used in fusion research to plasma thruster. CIEMAT researchers deploy a fast camera that analyzes fusion reactions at three different wavelengths.

Using this tool, Navarro and colleagues discovered turbulent structures in the plasma thrusts at smaller scales than they had ever seen. Now, the UC3M team can work on controlling their formation and improving thruster performance.

Validations in broader conditions

An added benefit of the two research teams working together was data sharing in areas in which they would not typically work. Nuclear fusion reactions occur at extremely high temperatures and are highly magnetized. Plasma thrusters operate at much lower temperatures, and the magnetic field is comparatively weaker.

But since turbulence occurs in both these conditions, the researchers shared data on its occurrence and validated computer models with wider set of conditions. This will also help fusion energy research in the future, a press release said.

The two teams were brought together as part of a technology transfer program organized by the EURO Fusion, but the collaboration has led to the development of newer research areas of common interest.

One such area is neutral particles and their influence on plasma. Neutral particles are complete atoms that do not behave like ions in plasma. When these particles interact with plasma, they cool it down.

“If we can study these phenomena under the conditions of fusion and space propulsion, we get a much more complete picture,” Hidalgo added in the press release.