Observation of Ionospheric Alfvén Resonator Signatures in the Earth's Ionosphere at Low Latitude: Implications for Ionospheric Modeling

The Communications/Navigation Outage Forecasting System (C/NOFS) satellite investigates the electrodynamics of the equatorial regions using a low inclination (13°) orbit with perigee and apogee of 401 and 867 km, respectively. The satellite is equipped with a three-axis double probe electric field detector that provides continuous DC and AC electric field measurements. Detection of Ionospheric Alfvén Resonator (IAR) signatures by C/NOFS offers unique means for investigating ionospheric electrodynamics, namely MHD (MagnetoHydroDynamic) wave propagation, ionospheric dynamics, aeronomy processes, and the Sun-Earth connection. In this work we present C/NOFS electric field measurements related to IAR signatures, and discuss the wave propagation and resonance mechanisms in the ionosphere. Peculiar electric field data offer new, complementary methodologies for inferring ionospheric electron and ion density profiles, and also contribute to the investigation of ionosphere dynamics. Specifically, IAR spectral signatures measured by C/NOFS allow for improving the International Reference Ionosphere (IRI) model, namely electron density and ion composition.