Fatima Ebrahimi of the PPPL labs has noticed that when magnetic bubbles called plasmoids form in the tokamak – thanks to the magnetic reconnection mechanism seen in the Sun during eruptions – these plasmoids whistle at a surprising rate. Finally, she devised a propulsion for spaceships that uses plasmoids.
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Fatima Ebrahimi with a spaceship. Credit: Elle Starkman, PPPL Office of Communications, and ITER.
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The universe is vast. In order to move in it, we need propulsion for spaceships. Contemporary propulsion is not exactly ideal, and scientists and visionaries are working on new propulsion concepts that could one day transport us through the solar system and perhaps beyond its borders.
Among them is the physicist Fatima Ebrahimi from the Princeton Plasma Physics Laboratory (PPPL), who came up with the concept of spacecraft propulsion, which would get us to Mars and beyond into the depths of the solar system in a reasonable time. At first glance, it is interesting in that it uses the mechanism of magnetic reconnection (magnetic reconnection), ie the short circuit of magnetic field lines, which occurs, for example, during solar flares or on Earth in tokamaks.
This propulsion, which its author calls the “Alfvenic reconnecting plasmoid thruster”, works by accelerating electrically charged plasma particles with plasma fields, which then fly out of the spacecraft’s engine, giving it traction and forward motion. Today, there are already spacecraft propulsions that use plasma. In those, however, electric fields move with the particles.
Princeton Plasma Physics Laboratory, logo.
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According to her own, Ebrahimi was not inspired by solar flares, but by somewhat less media-attractive research on the National Spherical Torus Experiment (NSTX) tokamak in PPPL laboratories. She noticed that during the experiments, due to magnetic reconnections, magnetic bubbles, called plasmoids, formed in the tokamak at speeds of around 20 kilometers per second. That seemed like a pretty decent move for the spaceship. Plasma particles inside the plasmoids fly out of its propulsion. Ebrahimi’s idea is actually a nice extension of fusion research.
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National Spherical Torus Experiment. Kredit: PPPL.
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Modern space drives with plasma and electric fields are not very powerful. Ebrahimi simulated her idea on PPPL computers as well as the National Ebrahimi Energy Research Scientific Computing Center at Lawrence Berkeley National Laboratory (LBNL). Simulations have shown that a new type of magnetic reconnection and plasmoid drive could be significantly more powerful than existing plasma drives.
Ebrahimi also states that its drive should be much more versatile than today’s plasma drives. For example, by being able to use any gas. Modern drives of this type require a gas with heavy atoms, such as xenon. The new drive seems to work in theory. The next step, as Ebrahimi resolutely says, will be a prototype.
Literature
Journal of Plasma Physics 21. 12. 2020.
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