Novel fusion device mimics the planets
A novel device built by MIT and Columbia University researchers suggests that nature’s way of trapping hot, ionized gases called plasma could one day provide a means of harnessing nuclear fusion. In their device, a half-ton, doughnut-shaped superconducting magnet levitated inside a huge vacuum vessel creates a magnetic field that—like the strong magnetic field around Jupiter—can hold onto plasma, even as temperatures and pressures rise.
Fusion occurs when light nuclei such as hydrogen combine to form heavier nuclei such as helium, generating vast amounts of energy in the process. But designing a device to capture that energy is difficult. Hydrogen nuclei are positively charged, so they repel one another. The trick, then, is to crowd hydrogen nuclei together and give them lots of energy so that they hit each other despite their repulsion. A device capable of confining hot, dense plasma long enough for fusion to occur could provide the world with abundant energy with virtually no harmful byproducts or greenhouse gas emissions.
For decades, researchers at MIT and elsewhere have been working on a confinement design called the tokamak, a giant doughnut-shaped vacuum chamber surrounded by magnets that send plasma particles spiraling inside the doughnut. But a team led by Jay Kesner, senior scientist at MIT’s Plasma Science and Fusion Center, and Michael Mauel, professor of applied physics at Columbia, is taking a different approach—an approach inspired by the planets.