A new type of rocket thruster propels a spacecraft by taking advantage of the physical mechanism that accelerates solar flares. The thruster would apply magnetic fields to force particles of electrically charged gas, or plasma, to shoot out the back of a rocket at high velocity, causing forward momentum.
The new thruster would propel a spacecraft far more efficiently than currently available plasma thrusters, which use electric fields to propel particles. That higher efficiency could bring the outer planets within reach of astronauts.
The novel thruster concept would accelerate ionized gas particles using magnetic reconnection, a process found throughout the universe — including on the surface of the sun as solar flares — in which magnetic field lines converge, suddenly separate, and then join together again, producing lots of kinetic energy.
Changing the strength of the magnetic fields can increase or decrease the amount of thrust. By using more electromagnets and more magnetic fields, the researchers can in effect turn a knob to fine-tune the velocity.
The new thruster produces movement by ejecting plasma particles contained in magnetic bubbles known as plasmoids. The plasmoids add power to the propulsion. This is the only thruster concept to incorporate plasmoids.
Ebrahimi’s thruster concept is unique in that it can use plasma created from gases with light atoms without performance degradation. This flexibility in fuel use could allow refueling using gases extracted by mining asteroids.
"If we make thrusters based on magnetic reconnection, then we could conceivably complete long-distance missions in a shorter period of time." – Fatima Ebrahimi
Fatima Ebrahimi, Principal Research Physicist, U.S. Department of Energy Princeton Plasma Physics Laboratory (PPPL)
Patent protection is pending. Princeton is seeking outside interest for the development of this technology.
U.S. Department of Energy
Head of Technology Transfer