Tag Archives: Transition to plastic regime for Rayleigh-Taylor instability in soft solids

Mayonnaise and nuclear fusion research?

Intriguing, eh? An August 6, 2023 news item on ScienceDaily announces an innovative approach to studying nuclear fusion energy,

Researchers are using mayonnaise to study and address the stability challenges of nuclear fusion by examining the phases of Rayleigh-Taylor instability. Their innovative approach aims to inform the design of more stable fusion capsules, contributing to the global effort to harness clean fusion energy. Their most recent paper explores the critical transitions between elastic and plastic phases in these conditions.

An August 6, 2024 Lehigh University (Pennsylvania, US) news release, which originated the news item, elaborates on the mayonnaise-fusion connection,

Mayonnaise continues to help researchers better understand the physics behind nuclear fusion.

“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,” says Arindam Banerjee, the Paul B. Reinhold Professor of Mechanical Engineering and Mechanics at Lehigh University and Chair of the MEM department in the P.C. Rossin College of Engineering and Applied Science. 

In simple terms, fusion reactions are what power the sun. If the process could be harnessed on earth, scientists believe it could offer a nearly limitless and clean energy source for humanity. However, replicating the sun’s extreme conditions is an incredibly complex challenge. Researchers across science and engineering disciplines, including Banerjee and his team, are examining the problem from a multitude of perspectives.

Inertial confinement fusion is a process that initiates nuclear fusion reactions by rapidly compressing and heating capsules filled with fuel, in this case, isotopes of hydrogen. When subjected to extreme temperatures and pressure, these capsules melt and form plasma, the charged state of matter that can generate energy. 

“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 their first paper on the topic back in 2019, Banerjee and his team examined that problem, known as Rayleigh-Taylor instability. The condition occurs between materials of different densities when the density and pressure gradients are in opposite directions, creating an unstable stratification. 

“We use mayonnaise because it behaves like a solid, but when subjected to a pressure gradient, it starts to flow,” he says. Using the condiment also negates the need for high temperatures and pressure conditions, which are exceedingly difficult to control.

Banerjee’s team used a custom-built, one-of-a-kind rotating wheel facility within Banerjee’s Turbulent Mixing Laboratory to mimic the flow conditions of the plasma. Once the acceleration crossed a critical value, the mayo started to flow. 

One of the things they figured out during that initial research was that before the flow became unstable, the soft solid, i.e., the mayo, went through a couple of phases.  

“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 says. “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 this transition between the elastic phase and the stable plastic phase is critical, he says, because knowing when the plastic deformation starts might tip off researchers as to when the instability would occur, Banerjee says. Then, they’d look to control the condition in order to stay within this elastic or stable plastic phase.

Here’s a link to and a citation for the latest paper,

Transition to plastic regime for Rayleigh-Taylor instability in soft solids by Aren Boyaci and Arindam Banerjee. Phys. Rev. E 109, 055103 – Published 15 May 2024 DOI: https://doi.org/10.1103/PhysRevE.109.055103

This paper is behind a paywall.

Jennifer Ouellette’s August 9, 2024 article for Ars Technica offers information that augments what can be learned from the news release, Note 1: For anyone who’s not a physicist is more accessible than the paper; Note 2: Links have been removed,

Inertial confinement fusion is one method for generating energy through nuclear fusion, albeit one plagued by all manner of scientific challenges (although progress is being made). Researchers at Lehigh University are attempting to overcome one specific bugbear with this approach by conducting experiments with mayonnaise placed in a rotating figure-eight contraption. They described their most recent findings in a new paper published in the journal Physical Review E with an eye toward increasing energy yields from fusion.

The work builds on prior research in the Lehigh laboratory of mechanical engineer Arindam Banerjee, who focuses on investigating the dynamics of fluids and other materials in response to extremely high acceleration and centrifugal force. In this case, his team was exploring what’s known as the “instability threshold” of elastic/plastic materials. Scientists have debated whether this comes about because of initial conditions, or whether it’s the result of “more local catastrophic processes,” according to Banerjee. The question is relevant to a variety of fields, including geophysics, astrophysics, explosive welding, and yes, inertial confinement fusion.

If you’re interested in learning more about inertial confinement fusion, Ouellette’s August 9, 2024 article will help.

As for fusion energy, there are many articles here; just use the search engine.