A team of researchers from the University of Rochester has found a way to turn liquid metal into plasma, the fourth state of matter and most abundant form of matter in the universe.
The effort, which is supported by the U.S. Department of Energy and the National Nuclear Security Administration, can lead to the realization of an alternative source of energy called controlled nuclear fusion and help scientists further understand stars and other celestial bodies.
Converting To Another Form Of Matter
Plasma comprises 99.9 percent of the observable universe, including the solar system's very own sun. It often behaves like gas, another form of matter. However, it has the capacity to conduct electricity and is affected by magnetic fields.
On Earth, plasma does not naturally occur; scientists can create an artificial plasma by heating gas in temperatures reaching thousands of degrees Fahrenheit. The same process is behind plasma television and neon lights.
However, researchers from the University of Rochester found another way to create plasma: by heating liquid metals to very high conditions. They believe it will produce a dense plasma.
"The transition to the latter has not been observed scientifically before and is precisely what we did," stated Mohamed Zaghoo, the first author of the study.
For the experiment, the researchers cooled the liquid metal deuterium to -422 degrees Fahrenheit. They then used Laboratory Laser Energetics' (LLE) OMEGA lasers at the University of Rochester to produce a strong shockwave that compressed the cooled deuterium to pressures up to five million times greater than atmospheric pressure. They also raised the temperature to 180,000 degrees Fahrenheit.
The liquid metal began completely transparent but turned shiny with high optical reflectivity as soon as the pressure and the temperature rose.
The study published in the Physical Review Letters revealed that liquid metal exposed to extreme conditions exhibit quantum properties. However, raising the temperature even higher can help the material transition to a plasma state.
"What is remarkable is that the conditions at which this crossover between quantum and classical occurs is different from what most people expected based on plasma textbooks," explained Suxing Hu, a senior scientist at LLE and a co-author of the study. " Furthermore, this behavior could be universal to all other metals."
Understanding Plasma
The researchers claimed that the findings of the study could help scientists understand how matter behaves in the extremes of the solar system. Zaghoo added that plasma makes up the vast interiors of astrophysical bodies, including brown dwarfs or objects formed when collapsing clouds of dust do not turn into a star. They are also called "failed stars" and scientists theorized that they contribute a great deal of mass in the universe.
He also stated that the study could aid future research to design experiments that could achieve thermonuclear fusion.
