A powerful solar storm in May 2024, dubbed “Gannon,” triggered an unprecedented collapse of Earth’s plasmasphere – a critical shield against harmful space radiation. Satellite data from Japan’s Arase mission revealed the protective layer shrunk to just 20% of its normal size, highlighting the vulnerability of near-Earth space to extreme solar events. This event, one of the strongest geomagnetic storms in over two decades, dramatically compressed Earth’s magnetic field, causing widespread disruption.
The Plasmasphere’s Critical Role
The plasmasphere is a doughnut-shaped region of charged particles that encircles Earth, co-rotating with the planet’s magnetic field. It acts as a buffer against high-energy particles from the sun, protecting satellites, radio signals, and navigation systems like GPS. Typically, the outer boundary of this region, the plasmapause, sits at roughly 27,340 miles (44,000 kilometers) above Earth.
Unprecedented Contraction During the Gannon Storm
During the May 2024 storm, the plasmapause plunged to only 5,965 miles (9,600 kilometers) within nine hours – an astonishingly rapid contraction. The Gannon storm was not a single event but a series of powerful solar eruptions that continuously bombarded Earth with plasma. The compressed magnetic field not only dragged the plasmasphere inward but also depleted it for over four days, the longest recovery period ever observed by the Arase mission.
The Role of “Negative Storms” in Prolonged Disruption
Researchers from Nagoya University discovered that the storm initially heated the polar regions intensely, then caused a drop in charged particles across the ionosphere, slowing down recovery. A “negative storm” effectively cut off the supply of fresh particles needed to replenish the plasmasphere. This interruption prolonged the collapse, demonstrating how interconnected Earth’s atmospheric layers become during extreme space weather.
Implications for Technology and Forecasting
The prolonged disruption can affect GPS accuracy, interfere with satellite operations, and complicate space weather forecasting. As solar activity continues to increase in the current solar cycle, understanding the speed of plasmasphere erosion and recovery is vital for safeguarding critical infrastructure on Earth. The findings, published in Earth, Planets and Space, underscore the growing need for improved space weather prediction and mitigation strategies.
The Gannon storm serves as a stark reminder of the sun’s potential to disrupt technology and underscores the importance of ongoing research into space weather dynamics. Continued monitoring and analysis will be critical to protecting our increasingly space-dependent society.
