Forget fuel-powered jet engines. We’re on the verge of having aircraft that can fly from the ground up to the edge of space using air and electricity alone.
Traditional jet engines create thrust by mixing compressed air with fuel and igniting it. The burning mixture expands rapidly and is blasted out of the back of the engine, pushing it forwards.
Instead of fuel, plasma jet engines use electricity to generate electromagnetic fields. These compress and excite a gas, such as air or argon, into a plasma – a hot, dense ionised state similar to that inside a fusion reactor or star.
Plasma engines have been stuck in the lab for the past decade or so. And research on them has largely been limited to the idea of propelling satellites once in space.
Berkant Göksel at the Technical University of Berlin and his team now want to fit plasma engines to planes. “We want to develop a system that can operate above an altitude of 30 kilometres where standard jet engines cannot go,” he says. These could even take passengers to the edge of the atmosphere and beyond.
The challenge was to develop an air-breathing plasma propulsion engine that could be used for take-off as well as high-altitude flying.
Plasma jet engines tend to be designed to work in a vacuum or the low pressures found high in the atmosphere, where they would need to carry a gas supply. But now Göksel’s team has tested one that can operate on air at a pressure of one atmosphere (Journal of Physics Conference Series, doi.org/b66g). “We are the first to produce fast and powerful plasma jets at ground level,” says Göksel. “These jets of plasma can reach speeds of up to 20 kilometres a second.”
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