A powerful solar storm that struck Earth in May 2024 has left behind two new, temporary radiation belts, one of which contains energetic protons, a phenomenon never observed before. The storm, a torrent of solar flares and particles, shook Earth's magnetic field and caused auroras to reach lower latitudes than usual.
Scientists, analyzing data from NASA's Colorado Inner Radiation Belt Experiment CubeSat, discovered the new belts sandwiched between Earth's two permanent Van Allen belts. The first belt, composed primarily of electrons, is a familiar occurrence after geomagnetic storms. However, the second belt, containing energetic protons, is unprecedented.
"When we compared the data from before and after the storm, I said, 'Wow, this is something really new'," says physicist Xinlin Li of the University of Colorado Boulder. "This is really stunning."
The new belts persisted for an unusually long time, lasting three months compared to the typical weeks of previous temporary radiation belts. Subsequent solar storms in June and August 2024 diminished the belts' density, but a small amount of particles remains. The proton belt, in particular, may persist for over a year.
The discovery has significant implications for satellite safety, as particles in Earth's orbit can pose a hazard to spacecraft. Scientists will continue to monitor the new belts to determine their longevity and the risks they may pose.