The coupling of an EUV coronal wave and ion acceleration in a Fermi-LAT behind-the-limb solar flare
In: ApJ 929 172 (2022); (2022)
Online
report
We present the Fermi-LAT observations of the behind-the-limb (BTL) flare of July 17, 2021 and the joint detection of this flare by STIX onboard Solar Orbiter. The separation between Earth and the Solar Orbiter was 99.2$^{\circ}$ at 05:00 UT, allowing STIX to have a front view of the flare. The location of the flare was ~S20E140 in Stonyhurst heliographic coordinates making this the most distant behind-the-limb flare ever detected in $>$100 MeV gamma-rays. The LAT detection lasted for $\sim$16 minutes, the peak flux was $ 3.6 \pm 0.8 $ (10$^{-5}$) ph cm$^{-2}$ s$^{-1}$ with a significance $>$15$\sigma$. A coronal wave was observed from both STEREO-A and SDO in extreme ultraviolet (EUV) with an onset on the visible disk in coincidence with the LAT onset. A complex type II radio burst was observed by GLOSS also in coincidence with the onset of the LAT emission indicating the presence of a shock wave. We discuss the relation between the time derivative of the EUV wave intensity profile at 193\angstrom\ as observed by STEREO-A and the LAT flux to show that the appearance of the coronal wave at the visible disk and the acceleration of protons as traced by the observed $>$100 MeV gamma-ray emission are coupled. We also report how this coupling is present in the data from 3 other BTL flares detected by Fermi-LAT suggesting that the protons driving the gamma-ray emission of BTL solar flares and the coronal wave share a common origin.
Comment: 10 pages, 9 figures
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The coupling of an EUV coronal wave and ion acceleration in a Fermi-LAT behind-the-limb solar flare
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Autor/in / Beteiligte Person: | Pesce-Rollins, Melissa ; Omodei, Nicola ; Krucker, Sam ; Di Lalla, Niccol`o ; Wang, Wen ; Battaglia, Andrea F. ; Warmuth, Alexander ; Veronig, Astrid M. ; Baldini, Luca |
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Quelle: | ApJ 929 172 (2022); (2022) |
Veröffentlichung: | 2022 |
Medientyp: | report |
DOI: | 10.3847/1538-4357/ac5f0c |
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