Part 2 of 2 Parts (Please read Part 1 first)
The International Thermonuclear Experimental Reactor (ITER) in France is an example of magnetic confinement fusion. ITER has recently been delayed until 2039 rather than 2035 which had previously been announced. The cost has risen an additional cost of five billion dollars.
The fusion method at ITER relies on very powerful magnetic fields to contain superheated plasma which is an ionized gas where fusion occurs. The plasma must be heated to temperatures ten times hotter than the sun’s core. It is confined within a doughnut-shaped vacuum chamber called a tokamak. The magnetic fields prevent the plasma from touching the walls of the chamber. If this occurs, it would cool down the plasma and stop the reaction.
Where does mayonnaise fit into all of this? A major challenge to stable nuclear fusion using inertial confinement is the Rayleigh-Taylor instability. This phenomenon occurs when different-density materials are subjected to opposing gradients of density and pressure.
This leads to unpredictable and often detrimental outcomes during the fusion process.
Arindam Banerjee is the Paul B. Reinhold Professor of Mechanical Engineering and Mechanics at Lehigh University. He and his team have turned to mayonnaise to aid their understanding of nuclear fusion. This condiment copies the behavior of more complex materials under pressure but in a more controlled setting.
Banerjee said, “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. We use mayonnaise because it behaves like a solid, but when subjected to a pressure gradient, it starts to flow.”
The new research findings build upon similar research from 2019. This prior research first examined the Rayleigh-Taylor instability problem in this context. Banerjee and his team employed a rotating wheel facility to simulate the flow conditions experienced by fusion plasma. They discovered that mayonnaise undergoes distinct phases. First, it behaves elastically, then plastically, before finally flowing unstably. Understanding these transitions is critical because it offers hints on how to control or delay the onset of instability in fusion capsules.
Banerjee and his team’s latest research goes deeper into the conditions that govern these phase transitions. The study identified specific criteria under which elastic recovery is possible. Elastic recovery is deemed vital for delaying or suppressing instability. These findings could guide the design of future fusion target capsules, ensuring that they remain stable under extreme conditions.
There is still a critical question. How applicable are these findings to actual fusion capsules in which the materials involved differ significantly in their properties? Banerjee and his team addressed this problem by non-dimensionalizing their data. This allows them to predict behaviors in fusion capsules despite the differences in material properties.
As Banerjee explains, his research is part of a global effort to make fusion energy on Earth a reality. By refining the understanding of fluid dynamics through such innovative experiments, researchers hope to bring us closer to a future powered by clean, limitless nuclear fusion energy.
Banerjee added, “We’re another cog in this giant wheel of researchers. We’re all working towards making inertial fusion cheaper and therefore, attainable.”