This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: In May 2024, Earth experienced its most intense geomagnetic storm since the Halloween storms of 2003. This "superstorm" filled night skies in many parts of the world with colorful aurorae, and it disrupted some infrastructure, such as GPS signals used by agricultural equipment.
Satellite observations revealed that during the storm, Earth's outer Van Allen radiation belt underwent a sudden, dramatic loss of highly energetic electrons. Xingzhi Lyu and colleagues now report the first comprehensive analysis of how this rapid electron transport occurred, with key implications for future space weather forecasting. Their study is published in the journal AGU Advances.
The Van Allen radiation belts are donut-shaped rings that encircle our planet and harbor energetic electrons and protons—mostly from the solar wind—trapped by Earth's magnetosphere. Geomagnetic storms can reconfigure the magnetosphere, causing sudden changes to electron dynamics in the outer radiation belt, which may be hazardous to satellites. Despite decades of research on these risks, the dynamics of rapid electron transport in the radiation belts during particularly extreme storms have so far been unclear.
The May 2024 superstorm presented a rare opportunity to study this phenomenon. The researchers analyzed data from the Japan Aerospace Exploration Agency's (JAXA) Arase satellite, quantifying the dramatic depletion of electrons from the outer radiation belt during the superstorm. To explore the physical processes behind the rapid loss, they simulated the event using the Versatile Electron Radiation Belt (VERB) model, which is designed to reproduce radiation belt dynamics.
They found that two previously studied processes were the primary drivers of the electron loss: magnetopause shadowing, which transported electrons outward and released them into space, and local wave scattering, which moved electrons inward into Earth's upper atmosphere. The relative dominance of each process differed in different regions of Earth's magnetic field. Importantly, for the simulations to accurately reproduce the real-world extreme electron loss, the onset of sudden, outward electron transport associated with magnetopause shadowing had to occur nearly simultaneously with a strong compression of Earth's magnetosphere that occurred during the superstorm.
This compression was followed by local wave scattering. Standard models of electron transport commonly used in space weather forecasting do not accurately capture the tightly coupled timing of superstorm dynamics and electron transport processes revealed in this study. The new findings could help guide development of better models, which could lead to more accurate superstorm forecasting and risk assessment.
Extract — continue reading at the source.
