Researchers Are Using Mayonnaise to Improve Nuclear Fusion Experiments

A team of researchers investigating the strength of capsules that contain fuel for fusion reactions have turned to a surprising ally in their quest for a better material: mayonnaise.

“We’re still working on the same problem, which is the structural integrity of fusion capsules used in inertial confinement fusion, and Hellmann’s Real Mayonnaise is still helping us in the search for solutions,” said Arindam Banerjee, a mechanical engineer at Lehigh University and co-author of the paper, in a university release. The team’s research was published earlier this year in Physical Review E.

Forget the mayonnaise for a second. What is nuclear fusion, again?

Nuclear fusion is the reaction that powers stars like our Sun. In short, it occurs when two or more light nuclei fuse to produce a heavier nucleus, generating a huge amount of power in the process. On Earth, harnessing such power would mean a reliable alternative to carbon-based energy sources, one that generates huge amounts of energy from initial reactions that use a lot less; at scale, it would mean a cleaner, greener future for our planet.

In laboratory settings, nuclear fusion is done in a couple different ways. One way is to use a torus-shaped device called a tokamak, which uses magnetic fields to control an internal plasma and induce fusion reactions. Another way is to blast a small pellet of fuel with lasers, causing fusion. The latter method is the way scientists at the Department of Energy’s National Ignition Facility generated a record-breaking amount of energy from their reaction in 2022. But that’s not to say that tokamaks are a bad way to go; earlier this year, the JET tokamak in the United Kingdom produced over 69 megajoules of energy, 20 times more energy than the National Ignition Facility reaction.

“At those extremes, you’re talking about millions of degrees Kelvin and gigapascals of pressure as you’re trying to simulate conditions in the sun,” says Banerjee. “One of the main problems associated with this process is that the plasma state forms these hydrodynamic instabilities, which can reduce the energy yield.”

In the pursuit of nuclear fusion that produces more energy than it consumes, both fusion methods will be useful. The different methods yield manifold insights about the practicality and efficiency of various aspects of the fusion process.

What’s mayo got to do with it?

Mayonnaise is an emulsion of egg, oil, and an acid like vinegar. Some people don’t like it. The condiment is also the key to a perfect grilled cheese (apologies if you disagree). But in this fusion research, mayonnaise helped the team probe an instability that occurs between materials of different densities when the gradients of density and pressure are moving oppositely.

“We use mayonnaise because it behaves like a solid, but when subjected to a pressure gradient, it starts to flow,” Banerjee said.

“As with a traditional molten metal, if you put a stress on mayonnaise, it will start to deform, but if you remove the stress, it goes back to its original shape,” he added. “So there’s an elastic phase followed by a stable plastic phase. The next phase is when it starts flowing, and that’s where the instability kicks in.”

Understanding precisely when the instabilities occur in the mayonnaise can help scientists control the conditions that give rise to the instabilities in the first place. By delaying or suppressing the instabilities, researchers working on confinement fusion can maintain the fusion reaction for longer.

The research team is lucky they went to the store before I did. Because if I had gotten there first, this mayo would have ended up slathered on a couple of slices of bread sizzling on a cast iron pan, instead of helping scientists explore the viability of a nuclear fusion-based future.