2025/04/01 by Aisling N. O'Hare, Aisling N. O’Hare, Сусанна Беккер +3 · 1 voice · 8 citations
Biochemistry, Genetics and Molecular Biology · Physics and Astronomy · #Astronomy #Astrophysics #Atmospheric sciences #Environmental science #Extreme ultraviolet lithography #Flare #Geomagnetism and Paleomagnetism Studies #Ionosphere #Ionosphere and magnetosphere dynamics #Optics #Physics #Solar and Space Plasma Dynamics #Solar flare #TEC #astro-ph.EP #astro-ph.SR
paper · pdf · doi:10.1029/2024ja033493
published in Journal of Geophysical Research Space Physics 130(4) (Wiley)
openalex publication_date 2025/04/01 · arxiv published 2025/04/10 · arxiv updated 2025/04/10 · openalex created_date 2025/04/28 · openalex updated_date 2026/08/05
Abstract The extreme ultraviolet (EUV) and X‐ray radiation emitted during solar flares has been shown to significantly increase the electron density of the Earth's ionosphere. During flares, quasi‐periodic pulsations in X‐ray flux originating in the corona have previously been linked to subsequent pulsations in the Earth's ionospheric D‐region. Similar pulsations have been detected in chromospheric EUV emission, although their impact on the Earth's ionosphere has not previously been investigated. Here, for the first time, synchronous pulsations were detected in solar EUV emission and ionospheric Total Electron Content (TEC) measurements. Using wavelet and periodogram analysis, we detect QPPs with approximately 85 s periods in chromospheric EUV emission lines (He ii 304 Å, C iii 977 Å, and H i 972 Å) from the Solar Dynamics Observatory Extreme Ultraviolet Variability Experiment during the impulsive phase of an X5.4 flare on 7 March 2012. These lines contribute to ionization in the ionospheric E‐ and F‐regions, resulting in subsequent variations of electron density with the same periodicity, which was detected in TEC measurements. This work demonstrates that the Earth's ionosphere is responsive to fine‐scale fluctuations in EUV emission during flares, with a time delay of approximately 30 s found. These findings may have applications in atmospheric modeling and solar‐terrestrial studies, including the calculation of ionospheric recombination rates.