2021/02/18 by R. P. Dufresne, G. Del Zanna, N. R. Badnell
Physics and Astronomy · #Astro and Planetary Science #Astrobiology #Astronomy #Astrophysics #Atmosphere (unit) #Atomic physics #Charge (physics) #Chromosphere #Collisional excitation #Computational physics #Corona (planetary geology) #Coronal mass ejection #Coronal radiative losses #Ion #Ionization #Line (geometry) #Meteorology #Nuclear physics #Physics #Plasma #Solar and Space Plasma Dynamics #Solar wind #Spectral line #Stellar, planetary, and galactic studies #astro-ph.SR #physics.atom-ph
paper · pdf · doi:10.1093/mnras/stab514
Accepted in MNRAS, 12 pages, 9 figures
arxiv created 2021/02/18 · openalex publication_date 2021/02/22 · arxiv updated 2021/03/03 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
ABSTRACT To predict line emission in the solar atmosphere requires models that are fundamentally different depending on whether the emission is from the chromosphere or the corona. At some point between the two regions, there must be a change between the two modelling regimes. Recent extensions to the coronal modelling for carbon and oxygen lines in the solar transition region have shown improvements in the emission of singly and doubly charged ions, along with Li-like ions. However, discrepancies still remain, particularly for singly charged ions and intercombination lines. The aim of this work is to explore additional atomic processes that could further alter the charge-state distribution and the level populations within ions, in order to resolve some of the discrepancies. To this end, excitation and ionization caused by both the radiation field and by atom–ion collisions have been included, along with recombination through charge transfer. The modelling is carried out using conditions which would be present in the quiet Sun. This allows an assessment of the part atomic processes play in changing coronal modelling, separately from dynamic and transient events taking place in the plasma. The effect the processes have on the fractional ion populations are presented, as well as the change in level populations brought about by the new excitation mechanisms. Contribution functions of selected lines from low-charge states are also shown, to demonstrate the extent to which line emission in the lower atmosphere could be affected by the new modelling.