A new type of rocket launcher that can lead humanity March and beyond has been proposed by a physicist in the U.S. Department of Energy (DOE) Princeton Plasma Physics Laboratory (PPPL)
The device would apply magnetic fields to induce plasma particles(link is external), electrically charged gas, also known as the fourth state of matter, to hit the back of a rocket and, due to momentum storage, propel the craft forward. Current space tested plasma propellants use electric fields to propel particles.
The new concept will accelerate particles using magnetic reconnection, a process found throughout the universe, including the surface of the sun, in which magnetic field lines converge, suddenly split and then reunite, producing a lot of energy. Reconnection also occurs within the donut-shaped union(link is external) devices known as tokamaks(link is external).
“I have been cooking this concept for a while,” said PPPL Leading Research Physicist Fatima Ebrahimi, the inventor of the concept and author of a paper(link is external) detailing the idea in Journal of Plasma Physics. “I had the idea in 2017 while sitting on a deck and thinking about the similarities between the discharge of a car and the high-velocity discharge particles created by the PPPL National Spherical Torus Experiment (NSTX)”, the predecessor of the main object of laboratory union. “During its operation, this tokamak produces magnetic bubbles called plasmoids that move at about 20 kilometers per second, which seemed very much like a push.”
Melting, the driving force of the sun and stars, combines light elements in the form of plasma – the hot, charged state of matter made up of free electrons and the atomic nucleus that represents 99% of the visible universe – to generate massive amounts of energy. . Scientists are looking to copy the union on Earth for a virtually inexhaustible supply of energy to generate electricity.
Current plasma injectors that use electric fields to drive particles can only produce low specific impulse, or velocity. But computer simulations performed on PPPL computers and the National Center for Scientific Energy Information Research, a Science Office User Office at Lawrence Berkeley National Laboratory in Berkeley, California, showed that the new plasma concept could generate exhaust with speed hundreds of miles in a second, 10 times faster than those of other drivers.
This faster speed at the beginning of a spaceship voyage could bring extraterrestrial planets within the reach of astronauts, Ebrahimi said. “Long-distance travel takes months or years because the specific impulse of chemical rocket engines is very low, so the craft needs some time to pick up speed,” she said. “But if we do propulsion based on magnetic reconnection, then we can complete long-distance missions in a shorter period of time.”
There are three main differences between the Abraham thruster concept and other devices. The first is that changing the strength of magnetic fields can increase or decrease the amount of thrust. “By using more electromagnets and more magnetic fields, you can actually turn a switch to adjust the speed,” Ebrahimi said.
Second, the new impeller produces motion by emitting both plasma particles and magnetic bubbles known as plasmids. Plasmids add power to propulsion and no other thruster concept incorporates them.
Third, unlike current thruster concepts that rely on electric fields, the magnetic fields in Abraham’s concept allow the plasma inside the thruster to consist of heavy or light atoms. This flexibility enables scientists to adjust the amount of propulsion for a particular mission. “While other propellants require heavy gas, made from atoms like xenon, in this concept you can use any kind of gas you want,” Ebrahimi said. Scientists may prefer light gas in some cases because smaller atoms can move faster.
This concept expands PPPL’s spatial propulsion research portfolio. Other projects include the Hall Thruster Experiment which was started in 1999 by PPPL physicists Yevgeny Raitses and Nathaniel Fisch to investigate the use of plasma particles to move a ship. Raitses and students are also investigating the use of small Hall propellers to give smaller satellites called CubeSats more maneuverability as they orbit the Earth.
Ebrahimi stressed that her thruster concept stems directly from her research into fusion energy. “This work was inspired by the work of the last fusion and this is the first time that plasmids and reconnection have been proposed for spatial propulsion,” Ebrahimi said. “The next step is to build a prototype!”
Reference: “An Alfvenic plasmoid thruster reconnect” by Fatima Ebrahimi, December 21, 2020, Journal of Plasma Physics.
DOI: 10.1017 / S0022377820001476
Support for this research came from funds from the Office of Science DOE (Fusion Energy Science) and Laboratory-led Research and Development (LDRD) made available through the Office of Science.