Plasma structures with different colors representing different charges and gas densities
James R. Beattie et al. 2024
The most detailed simulation of the chaotic supersonic plasma floating through our universe has revealed a complex map of swirling magnetic fields.
Clouds of charged particles, or plasmas, exist everywhere in our universe and can exist on small scales, such as the solar wind, or cover large distances, such as entire galaxies. These clouds experience turbulence similar to the air in Earth’s atmosphere, which determines key properties of the universe, such as how magnetic fields change in space and how quickly stars form.
However, the inherently chaotic nature of turbulence and the mixing of very different plasma velocities make it impossible to predict the behavior of plasma with mathematical precision.
now, james beatty Researchers at the Australian National University in Canberra and their colleagues ran the largest chaotic plasma simulation of its kind using the SuperMUC-NG supercomputer at the Leibniz Supercomputing Center in Germany.
The researchers set up a fixed plasma on a 10,000-cube grid and saw how turbulent currents artificially stirred the plasma, similar to stirring a cup of coffee. Beattie said the simulation would take 10,000 years to run on a standard single-core computer.
The complex structure of the plasma can be seen on a special piece of the simulation grid. The top half of the image shows the charge density. Red areas indicate high density and blue areas indicate low density. The bottom half of the image shows gas density. Yellow-orange indicates high density and green indicates low density. The white lines outline the resulting magnetic field lines.
In addition to teaching researchers how plasmas typically move through space, the simulations also included unexpected results, Beattie says. The team found that unlike the vortices in a cup of coffee, which must travel from large-scale vortices to the atoms themselves, the magnetic field movements from giant plasmas do not trickle down to very small scales.
“The mixing characteristics of large and small scales seem to be very different,” says Beattie. “It’s actually a lot less turbulent than you might expect on a smaller scale.”
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