This research, led by Professor Zong of Peking University in collaboration with the State Key Laboratory of Lunar and Planetary Science at Macau University of Science and Technology, has yielded new insights into energetic electron dynamics near Earth. The team employed the Medium-energy Electron Spectrometer onboard Macao Science Satellite-1 (MSS-1), which offers full pitch angle measurements i by Simon Mansfield
Sydney, Australia (SPX) Mar 26, 2025
This research, led by Professor Zong of Peking University in collaboration with the State Key Laboratory of Lunar and Planetary Science at Macau University of Science and Technology, has yielded new insights into energetic electron dynamics near Earth. The team employed the Medium-energy Electron Spectrometer onboard Macao Science Satellite-1 (MSS-1), which offers full pitch angle measurements in low-Earth orbit. MSS-1 consists of two satellites: MSS1-A, operating in a circular orbit at 450 km, and MSS1-B, traversing an elliptical path from 450 to 500 km altitude at a 41o inclination.
Using data collected by MSS-1, researchers have documented the first detection of a distinctive 'wisp' of electron precipitation within the South Atlantic Anomaly (SAA), a region where Earth's magnetic shielding is weakest and space weather effects are most pronounced. Typically, the SAA exhibits a depletion or 'rift' in particle flux, but this study reports an anomalous peak linked to human-made signals.
The cause, they found, is the interaction between energetic electrons in the radiation belts and Very Low Frequency (VLF) radio waves from the NWC ground-based transmitter in Australia. These waves alter the pitch angle of electrons, driving them toward Earth along specific trajectories. This creates a localized enhancement, or 'wisp,' in particle intensity, as well as a surrounding depletion zone.
What makes this observation unique is that MSS-1 identified the peak of the wisp inside the SAA rather than outside it, contradicting earlier findings. This result was made possible through the spectrometer's ability to detect electrons just outside the drift loss cone-a subtle range of pitch angles that previous satellites were unable to observe.
The team also distinguished between electrons still trapped in orbit and those precipitating into the atmosphere. By comparing these populations, they estimated that 2-5% of the trapped electrons were being scattered and lost due to VLF-induced effects, providing a rare quantitative measure of ground-based influence on radiation belt particles.
These results add critical evidence to our understanding of how terrestrial radio transmissions can shape near-Earth space environments and potentially affect satellite operations.
Research Report:Radiation belt electron wisp inside South Atlantic Anomaly due to terrestrial VLF transmitter observed by MSS-1
Related Links
State Key Laboratory of Lunar and Planetary Science, Macau
Space Technology News - Applications and Research