For the first time, researchers have measured how the violent space weather events known as geomagnetic superstorms disrupt the Earth’s protective plasmasphere, placing our critical infrastructure at risk.
Created by massive solar emissions of energy and charged particles, geomagnetic superstorms only occur about once every two decades. The focus of the new study published in Earth, Planets, and Space was the Gannon storm, also known as the Mother’s Day storm, which hit our planet on May 10-11, 2024.
Investigating a Geomagnetic Superstorm
Dr. Atsuki Shinbori from Nagoya University’s Institute for Space-Earth Environmental Research led the new study, determining for the first time what the impact of such a space weather event is on the plasmasphere and ionosphere. These storms can have serious consequences for space and ground-based communications networks, including GPS and timing signals essential to the modern internet.
Data for the research were sourced from the Japan Aerospace Exploration Agency’s Arase satellite, first launched in December 2016. The satellite was placed into orbit through the plasmasphere to measure plasma waves and magnetic fields as it studied radiation and energization in geospace. Eight and a half years into its mission, Arase was optimally positioned to make continuous observations of Earth’s plasmasphere during the extreme event. Those observations revealed evidence of rapid compression, followed by a slow recovery of the plasmasphere.
“We tracked changes in the plasmasphere using the Arase satellite and used ground-based GPS receivers to monitor the ionosphere—the source of charged particles that refill the plasmasphere,” Dr. Shinbori explained. “Monitoring both layers showed us how dramatically the plasmasphere contracted and why recovery took so long.”
The Plasmasphere
Typically extending to about 27,000 miles above the planet, the plasmasphere shields Earth’s surface and low-orbit satellites from dangerous radiation. During the Gannon storm, though, that protection was reduced to a meagre 6,000 miles out.
It only took nine hours from the time of the solar eruptions until those billions of changed particles had compressed the plasmasphere to its lowest point. The recovery was far slower, lasting for four days, and marking the longest recovery since the team began observing plasmasphere disturbances in 2017.
“We found that the storm first caused intense heating near the poles, but later this led to a big drop in charged particles across the ionosphere, which slowed recovery,” Dr. Shinbori noted. “This prolonged disruption can affect GPS accuracy, interfere with satellite operations, and complicate space weather forecasting.”
While the storm presented dangers to necessary infrastructure, it also allowed charged particles to reach much closer to the equator than usual, producing rare and beautiful low-latitude auroras. Normally, the auroral zone lies around the Arctic and Antarctic Circles, but the weakened magnetic field allowed it to seep down to Japan, Mexico, and southern Europe.
A Negative Storm
In the hour following the storm, charged particles in the upper atmosphere moved toward the poles—too late to be replenished by particles from the ionosphere. The standard replenishment time for these particles was nearly doubled on account of what researchers call a “negative storm,” an event in which rapid particle-level drops across large areas of the ionosphere, driven by heating, alter atmospheric chemistry. Only satellite observations can detect these strange and invisible events.
“The negative storm slowed recovery by altering atmospheric chemistry and cutting off the supply of particles to the plasmasphere,” Dr. Shinbori said. “This link between negative storms and delayed recovery had never been clearly observed before.”
Keeping an Eye on Geomagnetic Superstorms
This research provides a vivid new picture of what happens during these dangerous space weather events. Scientists now understand how the plasmasphere changes as energy flows through it.
Fallout from the event reinforced just how dangerous geomagnetic storms can be to our infrastructure, as GPS signals ceased, radio communications failed, and some satellites experienced electrical or transmission issues.
Altogether, by more clearly understanding these potentially catastrophic events, engineers can be much better equipped to design resilient space technology in the future.
The recent paper, “Characteristics of Temporal and Spatial Variation of the Electron Density in the Plasmasphere and Ionosphere During the May 2024 Super Geomagnetic Storm,” appeared in Earth Planets and Space on November 20, 2025.
Ryan Whalen covers science and technology for The Debrief. He holds an MA in History and a Master of Library and Information Science with a certificate in Data Science. He can be contacted at ryan@thedebrief.org, and follow him on Twitter @mdntwvlf.