Permanent magnets like those on fridges could speed development of fusion energy

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John Greenwald, Princeton Plasma Physics Laboratory
March 11, 2020

Stellarators, facilities used to develop fusion energy, the same power that fuels the sun and stars, are about to get a major overhaul.

Princeton researchers, such as Steven Cowley, the director of the Princeton Plasma Physics Laboratory (PPPL), are proposing to use permanent magnets, akin to those on refrigerators, to replace the complex array of twisted coils, which currently generate the magnetic fields that contain the super-hot gas called plasma in fusion reactions. These coils are the most expensive and complicated part of the stellarator.

The proposed magnets are called “rare earth, permanent magnets” and can generate powerful fields despite their small size. They are also unaffected by other fields nearby and do not need a power source.

Stellarators, invented in the 1950s by Princeton physicist Lyman Spitzer, Jr., are, along with tokamaks, the two major facilities used in the drive to develop fusion power. Although tokamaks are more widely used, these new, upgraded stellarators, which run without the risk of damaging heat bursts, or disruptions, potentially hold great promise for fusion energy.

“I am extremely excited about the use of permanent magnets to shape the plasma in stellarators,” said Cowley. “It leads to much simpler engineering design.”

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