NASA discovers Jupiter’s invisible shield is more complex than Earth’s

NASA's Juno spacecraft has revealed that Jupiter's bow shock, the invisible boundary where solar wind particles meet the planet's magnetic field, operates through a more complex system than Earth's equivalent. Led by researchers at the University of Iowa, the study found that Jupiter uses plasma waves at multiple frequencies to slow and heat incoming solar particles, compared to Earth's simpler single-frequency approach.

"Jupiter has found its own way to deal with the solar wind, through plasma waves that are stronger and exhibit richer harmonic structures," says Jayasri Joseph, a postdoctoral researcher in the Department of Physics and Astronomy at Iowa and the study's corresponding author. "That's important because if you have multiple frequencies, you can heat more particles in the solar wind and slow them down."

The research identified another difference. Before particles reach Jupiter's main bow shock, smaller shock structures called shocklets further slow the solar wind. Earth's bow shock typically handles this in a single region.

"Earth does not need to take these extra steps to handle the solar wind because the impact isn't as powerful," says Bill Kurth, a research scientist at Iowa's Department of Physics and Astronomy and study coauthor. Kurth has been part of the Juno mission since its 2011 launch.

The Juno Waves instrument, designed and built by University of Iowa physicists, measured electric and magnetic wave activity around Jupiter. The findings appeared online July 31 in Nature Communications in a paper titled "Plasma wave observations from Juno spacecraft at the Jovian bow shock."

The discovery could help scientists understand shock waves in extreme astrophysical environments. Jayasri Joseph notes that "Jupiter's bow shock offers a nearby natural laboratory for exploring and for understanding how nature converts enormous amounts of flow energy into heat and energetic particles," relevant to phenomena like supernova remnants.

Other contributors included Allison Jaynes, Jeremy Faden, and Chris Piker from the University of Iowa, along with researchers from NASA Goddard Space Flight Center, Southwest Research Institute, University of Colorado-Boulder, University of Minnesota, and Johns Hopkins University Applied Physics Laboratory.