A viable nuclear fusion reactor — one that spits out more energy than it consumes — could be here as soon as 2025.
That’s the takeaway of seven new studies, published Sept. 29 in the Journal of Plasma Physics.
If a fusion reactor reaches that milestone, it could pave the way for massive generation of clean energy.
During fusion, atomic nuclei are forced together to form heavier atoms. When the mass of the resulting atoms is less than the mass of the atoms that went into their creation, the excess mass is converted to energy, liberating an extraordinary amount of light and heat. Fusion powers the sun and stars, as the mighty gravity at their hearts fuse hydrogen to create helium.
But an enormous amount of energy is needed to force atoms to fuse together, which occurs at temperatures of at least 180 million degrees Fahrenheit (100 million degrees Celsius). However, such reactions can generate far more energy than they require. At the same time, fusion doesn’t produce greenhouse gases such as carbon dioxide, which drive global warming, nor does it generate other pollutants. And the fuel for fusion — such as the element hydrogen — is plentiful enough on Earth to meet all of humanity’s energy needs for millions of years.
“Virtually all of us got into this research because we’re trying to solve a really serious global problem,” said study author Martin Greenwald, a plasma physicist at MIT and one of the lead scientists developing the new reactor. “We want to have an impact on society. We need a solution for global warming — otherwise, civilization is in trouble. This looks like it might help fix that.”
Most experimental fusion reactors employ a donut-shaped Russian design called a tokamak. These designs use powerful magnetic fields to confine a cloud of plasma, or ionized gas, at extreme temperatures, high enough for atoms to fuse together. The new experimental device, called the SPARC (Soonest/Smallest Private-Funded Affordable Robust Compact) reactor, is being developed by scientists at MIT and a spinoff company, Commonwealth Fusion Systems.