A new source of magnetic storms is closer to Earth than expected

Magnetic storms have the potential to impact the daily lives of people all around the globe and to threaten satellites. A new study from the NASA THEMIS mission team has shown that magnetic storms can originate much closer to Earth than previously thought. The study is the first to show that the storms can form close to Earth and to indicate that the storms could overlap the orbits of weather, communication, and GPS satellites.Magnetic storms are responsible for producing the northern lights, but can also send hazardous particles towards spacecraft with the potential to put the spacecraft and satellites out of commission. Under the right conditions, the magnetic storms could disable the electrical grid, disrupt radio communications, and corrode pipelines.

Recent satellite observations have shown that magnetic storms can be initiated by magnetic reconnection much closer to Earth than previously thought possible. Magnetic reconnection happens when solar wind magnetic energy is transferred into Earth's magnetosphere, where it builds up until it converts into heat and particle acceleration. After decades of study, scientists aren't sure where exactly magnetic reconnection occurs during storms.

The trio of THEMIS satellites observed magnetic reconnection about three to four Earth diameters away from the planet. Scientists didn't think magnetic reconnection could happen in the comparatively stable magnetic field configuration near Earth. A weather satellite that was nearer to Earth in geostationary orbit detected energized particles that are associated with magnetic storms.

That satellite proved that the near-Earth reconnection stimulated ion and electron acceleration to high energies, posing a hazard to hundreds of satellites operating in the common orbit. The discovery will help scientists to refine models of how the magnetosphere responds to the solar wind to give more warning to get satellites and astronauts ready for potentially hazardous solar storms.