A private company betting on innovative fusion technology announced today that its latest device can maintain high temperatures over a long reaction time – a big step towards a reactor capable of producing more fusion energy than the device consumes. TAE Technologies is still far from that goal, which is also being pursued by huge government efforts. But his achievements so far have attracted $ 880 million in investment – more than any other private fusion company. The company has also announced plans to expand to a larger machine, which it hopes will achieve fusion conditions by 2025.
“The results seem like steady progress, but it’s far from a fusion device,” says plasma physicist Cary Forest of the University of Wisconsin-Madison. Still, he adds, “I’m in a fan camp.”
Fusion promises carbon-free energy that is generated from abundant fuels and produces limited radioactive waste. But for more than 7 decades, the goal has been elusive: extreme temperatures are needed to persuade the nuclei to overcome their natural repulsion and fusion. Most of the publicly funded efforts are focused on tokamaks, which use strong magnetic fields to enclose ionized gas in a donut-shaped vessel, where the plasma can be heated by microwave ovens and particle rays. The giant ITER reactor under construction in France is the culmination of such an approach. In other laboratories, such as the U.S. National Ignition Service, researchers crush tiny balls of fuel with powerful laser pulses to cause burst fusion.
Founded in 1998, TAE has an alternative approach. Its machines absorb hydrogen plasma into a spinning ring of smoke called the inverse field configuration (FRC). The swirling of the charged particles in the FRC creates a magnetic field that helps keep the plasma inside it. I am left, the vortex disintegrates in a fraction of a millisecond, but the TAE helps the FRCs to survive by firing a beam of particles tangentially into the edge of the ring, stiffening it and making it spin faster.
In TAE’s latest machine, which has been in operation since 2017 and is named Norman after company co-founder Norman Rostoker, FRCs are formed in a 30-meter-long tube that is bristled with control magnets, sensors and particle nozzles. The TAE now says Norman can maintain FRCs for 30 milliseconds and heat them with a beam of particles at temperatures of about 60 million degrees Celsius – better by a factor of 10 and 8, respectively, than the company’s previous devices. And CEO Michl Binderbauer says, “We can keep it as long as you want.” He says the lifespan of a FRC is limited only by the amount of energy they can store on site to power Norman magnets and particle rays and maintain the rings.
The TAE did not release its results, it was announced today in a press release. But others are impressed with the progress. “They focused on goals and achieved them on time, and that’s been lacking in fusion for a while now,” says fusion scientist Dennis Whyte of the Massachusetts Institute of Technology. “They are approaching the conditions necessary for [energy] profit, ”he says. But he points to several challenges. The electrons in Norman’s FRC are colder than the rest of the plasma, at only 10 million degrees Celsius. Cold electrons cause the inflow of incoming particles, reducing their efficiency. The FRC also leaks heat too quickly. Whyte says TAE will need to improve heat retention 1,000 times to achieve its goals. “It’s made good progress, but there’s still a way to get to us,” he says.
Whyte adds that plasma physics also has a habit of bringing surprises. “So far, TAE hasn’t seen the showstopper,” he says, “but you don’t know until you see him.” For example, in the 1980s, researchers built large tokamaks that they thought would be large enough to produce excess energy. But an unforeseen phenomenon called microturbulence appeared in the plasma, causing the heat to be dissipated faster than expected.
Binderbauer says the TAE is confident that its next machine, called Copernicus, will reach the following milestone: 100 million degrees Celsius, the temperature at which traditional fusion fuel – a mixture of the hydrogen isotopes deuterium and tritium – melts. The Copernicus will be up to 50% larger than the Norman, and will come with a power supply that can sustain the FRC for a few seconds. TAE plans to begin construction of the $ 250 million device later this year at a new location near the current facility at Foothill Ranch, California.
But the company has no plans to stop there. Tritium fuel has drawbacks: it is radioactive and difficult to obtain; and the deuterium-tritium reaction produces high-energy neutrons, which require dense protection to protect the machine and its operators. TAE wants to use alternative fuels of hydrogen and boron, abundant elements that produce far fewer neutrons when fused. But that reaction requires billions of degrees Celsius – and a future device larger than Copernicus, which TAE hopes to build by the end of the decade. “We’re pretty sure we have a theoretical basis,” Binderbauer says.
Investors seem to trust him. The company has attracted big-name financiers, including Paul Allen’s Vulcan Capital, Google, the Welcome Trust and the Kuwaiti government. Norman’s results alone helped TAE raise $ 280 million, and Copernicus is already funded with 50%. “A lot of people are impressed with how they opened the wallets of venture capitalists,” says Forest. “If they can keep the progress of this Moore’s law, maybe they can get there.”