Latest experimental plasma jet thruster uses only air and electricity

6 May 2020

Image: © rost9/

An experimental plasma jet thruster has been revealed that is not reliant on fossil fuels and uses the power of microwaves for propulsion.

As efforts to wean the aviation industry off engines powered by fossil fuels continue, researchers publishing to AIP Advances have proposed a prototype for a cleaner experimental engine. The researchers from the Institute of Technological Sciences at Wuhan University demonstrated a prototype device that uses microwave air plasmas for jet propulsion.

As the fourth state of matter, plasma exists naturally in places such as the sun’s surface and lightning on Earth. However, it can also be generated, leading the researchers to create a plasma jet by compressing air into high pressures and using a microwave to ionise the pressurised air stream.

Previous efforts to create plasma jet thrusters – such as NASA’s Dawn space probe that used xenon plasma – have not overcome the friction in Earth’s atmosphere, meaning they have not been powerful enough for aviation.

Helping to solve the climate crisis

Instead, the authors’ plasma jet thruster generates the high-temperature, high-pressure plasma in situ, using only injected air and electricity. The prototype device has shown itself to be able to lift a 1kg steel ball over a quartz tube 24mm in diameter, comparable in scale to the thrusting pressure of a commercial jet engine.

While working to improve on the thruster’s efficiency, the researchers said that by building a large array of these thrusters with high-power microwave sources, the prototype design could be scaled up to a full-sized jet.

“The motivation of our work is to help solve the global warming problems owing to humans’ use of fossil fuel combustion engines to power machinery, such as cars and airplanes,” said Jau Tang, one of the study’s authors.

“There is no need for fossil fuel with our design and, therefore, there is no carbon emission to cause greenhouse effects and global warming.”

Aircraft powered by electric propulsion have been increasingly in the spotlight, including a UK start-up that revealed a triple-wing, 18-seater hybrid electric aircraft last year.

Colm Gorey was a senior journalist with Silicon Republic