NASA is seeking to test a new propulsion system on the International Space Station. A scale-model test version of the Variable Specific Impulse Magnetoplasma Rocket (Vasimir) would be deployed. From the Flightglobal article:
The Vasimir involves the injection of a gas such as hydrogen into an engine that turns it into a plasma. That plasma is then energised further using radio signals as it flows through the engine, a process controlled by electromagnetic waves from superconducting magnets. Accelerated and heated through this process the plasma is focused and directed as exhaust by a magnetic nozzle. Vasimir is many times more efficient than conventional chemical rockets and far less fuel is needed.