Signatures of Helium Continuum in Cool Flare Loops Observed by SDO/AIA

0535752 - ASÚ 2021 RIV US eng J - Journal Article
Heinzel, Petr - Schwartz, P. - Lörinčík, Juraj - Koza, J. - Jejčič, S. - Kuridze, D.
Signatures of Helium Continuum in Cool Flare Loops Observed by SDO/AIA.
Astrophysical Journal Letters. Roč. 896, č. 2 (2020), č. článku L35. ISSN 2041-8205. E-ISSN 2041-8213
R&D Projects: GA ČR(CZ) GA19-17102S
Institutional support: RVO:67985815
Keywords : solar flares * solar coronal loops * solar extreme ultraviolet emission
OECD category: Astronomy (including astrophysics,space science)
Impact factor: 7.413, year: 2020
Method of publishing: Limited access
https://doi.org/10.3847/2041-8213/ab9839

We present an analysis of off-limb cool flare loops observed by the Solar Dynamics Observatory (SDO)/Atmospheric Imaging Assembly (AIA) during the gradual phase of SOL2017-09-10T16:06 X8.2-class flare. In the extreme-ultraviolet (EUV) channels starting from the 335 A one, cool loops appear as dark structures against the bright loop arcade. These dark structures were precisely coaligned (spatially and temporally) with loops observed by Swedish Solar Telescope (SST) in emission lines of hydrogen and ionized calcium. A recently published semi-empirical model of cool loops based on SST observations serves to predict the level of hydrogen and helium recombination continua. The continua were synthesized using an approximate non-LTE (i.e., departures from local thermodynamic equilibrium) approach and theoretical spectra were then transformed to AIA signals.
Permanent Link: http://hdl.handle.net/11104/0313693