The solar storm of May 2024, which caused auroras worldwide, also generated two temporary radiation belts. These belts were detected by NASA's Colorado Inner Radiation Belt Experiment (CIRBE) satellite, which had previously ceased operations due to a technical issue in April 2024 but reactivated in June.
CIRBE, designed to study Earth's Van Allen radiation belts, observed the formation of these new belts after the May solar storms, the most powerful geomagnetic event since March 1989. Typically, temporary radiation belts consist of high-energy electrons and last about four weeks. However, one of the new belts contained both high-energy electrons and a substantial amount of high-energy protons. The electron-dominated belt lasted three months, while the proton-dominated belt persisted even longer.
David Sibeck of NASA's Goddard Space Flight Center noted that these high-energy particles could remain in Earth's inner magnetic environment for an extended period. While solar storms can create radiation belts, they can also destroy them. A storm in June 2024 reduced the electron-dominated belt, and another in August nearly eliminated it. The proton-rich belt remained due to its location in a more stable region.
The existence of these temporary belts, with electron energies ranging from 1.3 to 5 megaelectronvolts (MeV) and proton energies from 6.8 to 20 MeV, poses risks to spacecraft and astronauts traveling through the Van Allen belts. The charged particles can damage spacecraft components and increase radiation exposure for astronauts. Future missions may need to adjust launch plans or incorporate additional shielding.
Ironically, the same solar storm that allowed CIRBE to make this discovery also led to its demise. The storm increased atmospheric drag, causing the satellite to de-orbit and burn up in October.