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Alfvén Waves Shown to Sustain Electric Fields That Power Auroral Arcs

Multi-spacecraft observations from NASA missions revealed energy flowing into auroral acceleration regions, validating a long-sought mechanism published in Nature Communications.

Overview

  • Researchers from the University of Hong Kong and UCLA identify Alfvén waves as the driver that maintains the stable electric potentials accelerating auroral electrons.
  • Coordinated measurements, including a 2015 auroral-arc event observed by military and NASA spacecraft together with NASA’s Van Allen Probes and THEMIS, supplied the multi-view dataset.
  • Analysis indicates wave energy continuously feeds the auroral acceleration zone, sustaining long-lived, field-aligned potential drops that would otherwise dissipate.
  • Electron measurements show characteristic inverted V–shaped spectra that diagnose a steady potential structure above luminous arcs.
  • Similar signatures recorded by Juno at Jupiter point to a common wave-driven process across planetary magnetospheres with consequences for space weather, satellites, and high-latitude communications.