Strong solar activity involving the release of substantial energy and charged particles can lead to disturbance in the Earth’s atmosphere, known as a geomagnetic storm. This can affect the near-Earth space environment for several days. The finding origins from research by Japan’s Institute for Space-Earth Environmental Research (ISEE) – Nagoya Institute of Technology, and National Institute of Information and Communications Technology (NICT).
The team observed the effects of a super geomagnetic storm that occurred on May 10, 2024. By analyzing data from the Global Navigation Satellite System (GNSS) and Japan’s geo-space exploration satellite Arase, the researchers showed that the plasmasphere – a plasma-containing near-Earth region of space – was severely suppressed by the geomagnetic storm. Only after four days had the region recovered to its state before the geomagnetic storm.
The results help in understanding the interplay between the Earth’s outer atmosphere and the space environment. This, in turn, has implications for the accuracy of communication signals, satellites operations, and human spaceflight.
The strongest storm in 21 years
The near-Earth space environment is shaped by solar activity. This is not least true for two regions, which are the ionosphere and the plasmasphere.
The ionosphere, located between 60 and 1,000 km altitude, contains ionized particles formed by ultraviolet and X-ray radiation. The plasmasphere is a dense region of low-energy plasma originating from the ionosphere, located inside the Earth’s magnetosphere.
The geomagnetic storm of May 10, 2024, was the most intense in approximately 21 years. Low-altitude auroras were visible across the globe.
During the storm, the Arase satellite operated by the Japan Aerospace Exploration Agency (JAXA), and global GNSS receiver networks detected rapid changes in the structure of the plasmasphere.
Severe drop in electron density
The research team combined ionospheric total electron content (TEC) data obtained from GNSS receiver networks with electron density data collected by Arase to analyze how ionospheric disturbances influenced recovery of the plasmasphere.
The analysis revealed that the plasmasphere required more than four days to recover after the storm. A study of 77 geomagnetic storms which occurred between March 2017, and December 2024 confirmed that the May 2024 event exhibited an unusually prolonged recovery period.
Moreover, TEC observations indicated that ionospheric electron density decreased by 50-90% across the Northern Hemisphere during the storm. These findings demonstrate that the delayed recovery of the plasmasphere was caused by suppressed plasma supply from the ionosphere.
The findings contribute to the advancement of space weather forecasting models and are expected to improve the accuracy of satellite communication and navigation predictions in the future.
Source: “Successful Observation of Space Environment Variations Induced by a Super Geomagnetic Storm”, Topics, National Institute of Information and Communications Technology (NICT), and Institute for Space-Earth Environmental Research (ISEE) – Nagoya Institute of Technology.
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