New computer model helps bring the sun into the lab – sciencedaily

Every day, the sun ejects large amounts of a hot particle soup known as plasma toward Earth, where it can disrupt telecommunications satellites and damage power grids. Now, scientists at the Princeton Plasma Physics Laboratory (PPPL) of the United States Department of Energy (DOE) and the Department of Astrophysical Sciences at Princeton University have made a discovery that could lead to better predictions of this. space weather and help protect sensitive infrastructure.

The discovery comes from a new computer model that predicts the behavior of plasma in the region above the sun’s surface known as the solar corona. The model was originally inspired by a similar model that describes the behavior of plasma that powers fusion reactions in donut-shaped fusion facilities called tokamaks.

Fusion, the power that drives the sun and stars, combines light elements in the form of plasma – the hot, charged state of matter made up of free electrons and atomic nuclei – which generates massive amounts of energy. Scientists seek to replicate fusion on Earth for a virtually inexhaustible supply of energy to generate electricity.

Princeton scientists made their discoveries by studying the interconnected magnetic fields that loop in and out of the sun. Under certain conditions, curls can cause hot particles to erupt from the sun’s surface in huge burps known as coronal mass ejections. These particles can eventually strike the magnetic field surrounding the Earth and cause the Northern Lights, as well as interfere with electrical and communication systems.

“We need to understand the causes of these flares to predict space weather,” said Andrew Alt, graduate student of the Princeton program in plasma physics at PPPL and lead author of the article reporting the results in the Astrophysics Journal.

The model is based on a new mathematical method that incorporates new insight that Alt and his collaborators discovered into the causes of instability. Scientists have discovered that a type of shake known as “torus instability” can cause strung magnetic fields to detach from the sun’s surface, triggering a flood of plasma.

The instability of the torus loosens some of the forces that keep the strings attached. Once these forces weaken, another force causes the strings to expand and lift further from the solar surface. “The ability of our model to accurately predict the behavior of magnetic strings indicates that our method could ultimately be used to improve space weather forecasts,” Alt said.

Scientists have also developed a way to more accurately translate lab results into sunlight conditions. Earlier models relied on assumptions that facilitated calculations but did not always simulate plasma accurately. The new technique relies solely on raw data. “The assumptions built into previous models remove the important physical effects that we want to account for,” Alt said. “Without these assumptions, we can make more accurate predictions.”

To conduct their research, scientists created magnetic flux ropes inside PPPL’s ​​Magnetic Reconnection Experiment (MRX), a barrel-shaped machine designed to study the melting and explosive breaking of field lines. magnetic in plasma. But flux cords created in the laboratory behave differently from cords on the sun, since, for example, flux cords in the laboratory must be contained in a metal container.

The researchers modified their mathematical tools to account for these differences, thus ensuring that the results of MRX could be translated in the sun. “There are conditions on the sun that we cannot mimic in the lab,” said PPPL physicist Hantao Ji, a professor at Princeton University who advises Alt and has contributed to the research. “So we adjust our equations to account for the absence or presence of certain physical properties. We need to make sure that our research compares apples to apples so that our results are accurate.”

The discovery of plasma flickering behavior could also lead to more efficient generation of fusion-fueled electricity. Magnetic reconnection and associated plasma behavior occurs in tokamaks as well as on the sun, so any insight into these processes could help scientists control them in the future.

Support for this research came from the DOE, the National Aeronautics and Space Administration and the German Research Foundation. Research partners include Princeton University, Sandia National Laboratories, Potsdam University, Harvard-Smithsonian Center for Astrophysics and the Bulgarian Academy of Sciences.

Source of the story:

Material provided by DOE / Princeton Plasma Physics Laboratory. Original written by Raphael Rosen. Note: Content can be changed for style and length.

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