Nagoya University researchers used the Arase satellite to capture unprecedented data from the May 2024 Gannon superstorm—the strongest geomagnetic event in over 20 years. The storm compressed Earth's plasmasphere to just one-fifth its normal size, disrupting navigation and communication systems worldwide.

Scientists documented the extreme compression and surprisingly slow four-day recovery, driven by a "negative storm" that reduced ionospheric particle flow. Published in Earth, Planets and Space, these findings could revolutionize space weather forecasting and better protect our technology infrastructure. The storm's intensity even triggered rare low-latitude auroras visible in unusual regions around the globe.