2025/01/06 by Magnus F. Ivarsen, Ivarsen, Magnus F, St-Maurice, Jean-Pierre +12
Earth and Planetary Sciences · Engineering · #Earth and Planetary Astrophysics (astro-ph.EP) #Earthquake Detection and Analysis #FOS: Physical sciences #Geophysical and Geoelectrical Methods #Geophysics (physics.geo-ph) #Geophysics and Sensor Technology #Space Physics (physics.space-ph)
paper · pdf · doi:10.48550/arxiv.2501.03174
openalex publication_date 2025/01/06 · openalex created_date 2025/01/08 · openalex updated_date 2026/08/01
During the 23 April 2023 geospace storm, we observed chorus wave-driven, energetic particle precipitation on closed magnetic field lines in the dayside magnetosphere. Simultaneously and in the ionosphere's bottom-side, we observed signatures of impact ionization and strong enhancements in the ionospheric electric field, via radar-detection of meter-scale turbulence, and with matching temporal characteristics as that of the magnetospheric observations. We detailed this in a companion paper. In the present article, we place those observations into context with the dayside ionosphere, and describe a remarkably similar event that took place during the May 2024 geospace superstorm. In both cases, fast, eastward-moving electric field structures were excited equatorward of the ionospheric cusp, on closed magnetic field-lines -- observations that challenge existing modes of explanation for electrodynamics in the cusp-region, where most such observations are interpreted in the context of poleward-moving auroral forms. Instead, primarily eastward-moving electric field structures were associated with turbulent Hall currents that are perhaps characteristically excited during geospace storms by wave-particle interactions near magnetospheric equator or by proton precipitation characteristics in the cusp, forming a `parallel-plate capacitor-like effect'. We propose that transient eastward electrodynamic bursts in the dayside ionosphere might be a common, albeit previously unresolved, feature of geomagnetic storms.