2025/02/25 by Yangyang Shen, Shen, Yangyang, Xu Zhang +17 · 1 voice
Earth and Planetary Sciences · Physics and Astronomy · #Earth and Planetary Astrophysics (astro-ph.EP) #Earthquake Detection and Analysis #FOS: Physical sciences #Geophysics (physics.geo-ph) #Ionosphere and magnetosphere dynamics #Lightning and Electromagnetic Phenomena #Plasma Physics (physics.plasm-ph) #Space Physics (physics.space-ph) #astro-ph.EP #physics.geo-ph #physics.plasm-ph #physics.space-ph
paper · pdf · doi:10.48550/arxiv.2502.18692
openalex publication_date 2025/02/25 · arxiv published 2025/02/25 · arxiv updated 2025/02/25 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Auroral streamers are important meso-scale processes of dynamic magnetosphere-ionosphere coupling, typically studied using imagers sensitive to energetic (>1 keV) electron precipitation, such as all-sky imagers (ASIs). This paper reports streamer-like red-line auroras, representing low-energy (<1 keV) precipitation, observed poleward of a black aurora and an auroral torch. These red-line auroras were associated with a magnetospheric electron injection and braking ion flows. Observations were made using the THEMIS spacecraft and ground-based imagers, including the ASI, REGO, and meridian scanning photometer (MSP) at Fort Smith. We identify plasma sheet electron pitch-angle scattering by time-domain structures (TDSs) and electron cyclotron harmonics (ECH) waves as the driver of these red-line auroras, because of (1) a strong correlation (~0.9) between observed red-line intensities and precipitating fluxes; (2) consistent red-line intensities from auroral transport code forward modeling, and (3) consistent precipitation characteristic energies from MSP optical inference and quasi-linear estimates.