Year: 2024
Type: article
Abstract: Solar flares have profound impacts on the lower ionosphere and long‐distance radio propagation. Extremely low frequency (ELF: 3–3,000 Hz) waves are challenging to observe and experience unique interactions with the lower ionosphere. The primary natural sources of ELF waves are thunderstorm lightnings across the globe. Using a newly developed azimuth determination technique and improved observation hardware we show that ELF attenuation in the Earth‐Ionosphere spherical cavity decreases and propagation velocity increases under the influence of an M‐class solar flare. Using a two‐parameter model of the lower ionosphere, the observations are shown to be consistent with increased electron density and sharper gradients in the D‐region resulting from X‐ray radiation. The sharper electron density gradient is primarily responsible for the propagation velocity increase, suggesting a unique capability that ELF observations can bring to global remote sensing of the lower ionosphere under space weather perturbations.
DOI: 10.1029/2024ja033083
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $3,880
Awards: G2074250371, G2953162778, G298428782, Collaborative Research: Remote Sensing of the Lower Ionosphere during 2024 Solar Eclipse: Revealing the Spatial and Temporal Scales of Ionization and Recombination, Controlled Whistler Mode Wave Injection Experiments with the High Altitude Auroral Research Program (HAARP) Facility, G8304482539
OpenAlex ID: W4404911762