Nuclear Fusion Scientists Have Used Magnets to Steer Reactions

Scientists have further developed a way of controlling nuclear fusion reactions, marking another forward step in the rush to achieve a clean, virtually limitless source of energy.

Nuclear fusion refers to the process of joining two atomic nuclei together to form one single heavier nucleus. When this happens, the mass of the single atom is slightly less than that of the combined masses of the two original atoms, and this leftover mass is released as energy.

It's the same process that powers our sun, where hydrogen atoms are fused together to form helium atoms under intense heat and pressure.

Scientists have been trying to recreate this process on Earth for years to harness the energy released. If they can pull it off, fusion promises to be a clean and almost limitless source of energy that should also be safer than current nuclear reactors.

However, scientists have yet to achieve a nuclear fusion reaction that produces more energy than it consumes. It's also been a struggle to keep a fusion reactor running for long enough to make it viable for the connection to a national power grid.

On Earth, scientists achieve fusion by recreating the sun's heat in a lab. However, these reactions need to be very carefully controlled. If not, fusion won't occur and the hot conditions could damage the reactor.

One method scientists have used to achieve fusion in the lab is by focusing lasers on a small capsule of fuel to compress it into a tiny point, creating temperatures similar to those seen in the core of the sun. This method is known as inertial confinement fusion.

Previously, scientists had contained this reaction in a gold case, with the lasers hitting the container itself rather than the fuel inside. Now, researchers at the University of Delaware and other institutions have developed a method in which the lasers hit the fuel directly, and the reaction is contained by strong magnets instead.

These magnets create magnetic field strengths of 50 Tesla. By comparison, MRI machines used in medical scans—which are strong enough to pull metal objects across the room—create strengths of above 3 Tesla.

It's far from the first time that magnets have been used to steer nuclear reactions. Scientists have used magnets to run nuclear fusion reactors called tokamaks for decades, though these have yet to overcome the hurdle of providing more power than they consume. Still, the use of magnets in inertial confinement fusion is an interesting twist.

University of Delaware researcher Arijit Bose, who has been pursuing the approach along with colleagues, said in a press release: "You want the nuclei to fuse. The magnetic fields trap the charged particles and make them go around the field lines. That helps create collisions and that helps boost fusion. That's why adding magnetic fields has benefits for producing fusion energy."

The research is still in its early stages, but Bose and the team found for the first time that applying the magnetic field to the reaction flattened the shape of the implosion.

Scientists have considered applying magnetic fields to inertial confinement fusion reactions before, but until now most efforts have been on paper rather than in the lab.

Inertial confinement fusion is just one method scientists have used to get reactions going. Other methods involve creating plasma—an electrically charged gas—and using magnets to circulate it around tokamaks.

Despite promising breakthroughs and developments in recent years, a working nuclear reactor has so far remained out of reach—though some optimistic scientists think fusion power could be on the grid within the next decade.

"We won't have a solution tomorrow," Bose said. "But what we're doing is contributing to a solution for clean energy."