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Graduate student Alexandra Levines stands next to part of a stellar device, a twisted fusion device designed to entrap superheated plasma to facilitate fusion reactions. Credit: Elle Starkman, Princeton University
Scientists have found a mathematical shortcut that could help harness fusion energy, a potential source of clean electricity that could mitigate floods, heat waves and other growing effects of climate change. This method allows researchers to more easily predict how well the stellar apparatus — a quirky device designed to reproduce the fusion energy that powers the sun and stars — will be able to retain the heat needed for fusion reactions.
This technique measures how well the star’s magnetic field is able to stick to the faster-moving atomic nuclei in the plasma, which increases the overall heat and aids fusion reactions. But how can scientists find a shape that holds as much heat as possible?
Find magnetic cages that retain heat
said Alexandra Levines, graduate student in plasma physics at the US Department of Energy (DOE) Princeton Plasma Physics Laboratory (PPPL). “Instead, we have to use an acronym,” said Levines, lead author of the paper reporting the findings in the journal. Nuclear fusion.
“This research shows that we can find the best shape of the magnetic field for confining heat by calculating something easier – how far fast particles are drifting away from the curved magnetic field surfaces in the center of the plasma,” Levines said. “This behavior is described by a number known as gamma C, which we detected as a constant consistent with confinement of the plasma.”
In fact, the acronym advances future star research, Levinis said, “because the faster the particles stay in the center of the plasma, the hotter the fuel and the more efficient the stellar device.”
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Current density profiles calculated by SFINCS code against the radial coordinate of three expanded balances compared to their original values. credit: Nuclear fusion (2022). DOI: 10.1088/1741-4326/aca4e3
History and future of merger
Fusion releases massive amounts of energy by combining the elements of light into the form of plasma – the hot, charged state of matter made up of free electrons and atomic nuclei that make up 99% of the visible universe. Scientists around the world are seeking to harness fusion reactions to create an almost inexhaustible supply of safe, clean energy to generate electricity.
PPPL has more than half a century of experience developing theoretical scientific knowledge and advanced engineering to enable integration to support the United States and the world. At the same time, the lab has long advanced the basic scientific understanding of the plasma universe from laboratory to astrophysical scales.
Stellarators, developed by PPPL founder Lyman Spitzer in the 1950s, operate without the risk of perturbations caused by donut-shaped fusion devices called tokamaks face. But stellar stars have long been unable to retain heat as well as tokamak, which have similar magnetic fields.
“But using techniques like the one LeViness studied, we’ve been able to find magnetic configurations of stars that contain heat as well as the tokamak canister,” said Elizabeth Ball, assistant professor of applied physics at Columbia University. “It’s more difficult for the stars, but LeViness has helped show that it’s possible,” said Paul, a former Presidential Fellow at Princeton University.
more information:
Alexandra LeViness et al, Active particle optimization of the quasi-axial stellar equilibrium, Nuclear fusion (2022). DOI: 10.1088/1741-4326/aca4e3
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