Geoff Reeves Publishes Exciting Space Weather Research in Journal of Geophysical Research
Geoff Reeves Publishes Exciting Space Weather Research in Journal of Geophysical Research
Geoff Reeves, a scientist with Los Alamos National Laboratory (LANL) and the New Mexico Consortium, recently published an article titled, Multi‐Platform Observations of the Radial Penetration of Substorm Injected Electrons and Subsequent Slot‐Filling Event, in The Journal of Geophysical Research – Space Physics.
This research looks at a space-weather event that happened on February 15, 2018, when a disturbance in the solar wind struck Earth and triggered a moderate geomagnetic storm. Earth is surrounded by the Van Allen radiation belts, which are zones where high-energy particles, especially electrons, get trapped by Earth’s magnetic field. During storms, these electrons can suddenly surge and move inward, creating hazards for satellites, communications, and astronauts. Early in this particular storm, there was a strong “substorm injection,” meaning a fast, sudden delivery of energized electrons from the far side of Earth’s magnetic field into regions closer to the planet.
What made this event unusually valuable is that it was observed at the same time by a large network of satellites and ground instruments. LANL spacecraft, NASA’s Van Allen Probes, Japan’s Arase satellite, polar-orbiting MetOp/POES satellites, and ground sensors in North America all captured the action. Because so many instruments viewed the same process from different locations, the researchers could measure details that are usually too hard to determine clearly in other storms.
One major result is that the substorm-injected electrons penetrated much closer to Earth than is usual, well inside geosynchronous orbit where many communications satellites operate. A lucky alignment between two satellites with one moving inward toward Earth and the other outward at the same magnetic local time. This allowed the team to pinpoint the inner edge of the injection region. The supporting ground observations reinforced the spacecraft measurements.
The study also explains the origin of a specific type of electromagnetic wave called whistler-mode hiss inside the plasmasphere, a region of relatively dense cold plasma around Earth. The team’s analysis showed that these waves were generated by the injected electrons drifting around Earth, rather than by some unrelated background process. This matters because these waves can scatter electrons and help reshape the radiation belts during storms.
Reeves and colleagues looked at the question of “slot filling,” the process where storms pack energetic electrons into the normally sparse region between Earth’s two radiation belts, raising risks for satellites. Past studies couldn’t tell if this was just part of a substorm injection, but these observations showed electrons reached the slot hours later via a separate transport step. This means slot filling is a distinct, later phase of storm evolution, improving space-weather forecasting and satellite protection.
To learn more about this exciting research read the entire article at: Multi‐Platform Observations of the Radial Penetration of Substorm Injected Electrons and Subsequent Slot‐Filling Event.