Japanese scientists have discovered that during powerful magnetic storms, the ring current that weakens Earth’s magnetic field is primarily generated not by the solar wind, as previously believed, but by particles of terrestrial origin. This conclusion was reached after analyzing the most severe geomagnetic storm in the past two decades, which occurred in May 2024.
Researchers from Nagoya University were able, for the first time, to determine the origin of the particles forming the ring current during such an intense magnetic storm. It turned out that approximately 85% of the ions creating this enormous stream of charged particles originate from the upper layers of Earth’s atmosphere.
The ring current is a belt of charged particles located at an altitude ranging from 19,000 to 51,000 kilometers above the planet’s surface. During powerful magnetic storms, it generates its own magnetic field, which partially diminishes Earth’s natural protective barrier. Moreover, this process can amplify induced currents in power lines, pipelines, and other ground-level infrastructure.
For a long time, scientists were unable to reach a consensus on the primary source of the ring current’s particles—whether it was the solar wind or Earth’s atmosphere. The answer came thanks to Japan’s scientific satellite “Arase,” which, during the magnetic storm on May 10–11, 2024, found itself in an ideal position to observe the interaction between solar plasma streams and our planet’s magnetosphere.
In the course of the study, specialists analyzed the mass and energy of ions within the magnetosphere and compared them with the parameters of the solar wind. Despite the fact that, at the height of the storm, the inner region of the magnetosphere shrank by roughly 80%, heavy ions rising from Earth’s atmosphere continued to constitute the majority of the ring current.
The authors of the study believe their findings will enhance our understanding of how matter is exchanged between the atmosphere and the planet’s magnetosphere. In the long term, this could enable more accurate forecasting of the impacts of powerful magnetic storms on satellites, navigation systems, power lines, and other critical infrastructure.
The magnetic storm on May 10–11, 2024, reached the highest level, G5, for the first time since August 2005. It triggered auroras far beyond their usual latitudes and caused disruptions in some navigation and telecommunications systems.
About the Author
