The first 3D model of Earth’s magnetosphere could help us better understand how satellites cope with space weather
The magnetic fields that surround some planets, such as Earth, have been recreated in miniature in the lab. The 3D model may give us a better idea of how space weather affects satellites.
Any magnetised object that is immersed in a stream of electrically charged particles will be able to affect the movement of those particles. The region around the object in which this effect is seen is called a magnetosphere. Earth has a magnetosphere, and it acts like a shield against charged particles from the sun known as cosmic rays, says Derek Schaeffer at Princeton University.
“For Earth, it controls all kinds of space weather and things like auroras and whether space satellites get destroyed or not,” he says.
Now, Schaeffer and his colleagues have developed a 3D model that can recreate these magnetospheres in miniature. “Physics works in multidimensions and this gives us a better representation of what is actually happening in a magnetosphere,” he says.
The researchers used the Large Plasma Device at the University of California, Los Angeles, which helped them mimic the magnetic field operating across the entire solar system, while a rapidly firing laser created plasmas that replicated the solar winds containing fast-moving charged particles. Then, a small donut-shaped magnet acted as a magnetic planetary body – like Earth – orbiting the sun.
Studying the system allows the team to explore the behaviour of magnetospheres in 3D, says Schaeffer. “Solar winds warp the magnetic field and kind of compress it – it drives all these different processes, such as space weather,” he says.
The work is an improvement on previous 1D lab models of magnetospheres. Although it is also possible to study the magnetospheres of Earth and other planets directly by sending spacecraft to collect data, doing so is logistically difficult, says Schaeffer. “There’s lots of gaps in the data,” he says. “There’s only so many spacecrafts and it takes a long time for them to sample a lot of different parts of the magnetosphere.”
The new lab-based magnetosphere model will be useful for researchers who want to test their theoretical models, says Schaeffer. This could help them determine how satellites might fare in space.
“This sort of experiment does provide an interesting, direct way to probe the physics of the interaction between a stellar wind and a magnetised planet,” says Steve Milan at the University of Leicester in the UK. But he says he is unsure how useful it will be to model the more complex phenomena seen in magnetospheres, such as auroras.
Journal reference: Physics of Plasmas, DOI: 10.1063/5.0084353
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