Publication | Closed Access
Energy balance in the solar transition region. III - Helium emission in hydrostatic, constant-abundance models with diffusion
759
Citations
0
References
1993
Year
Previous work established the mathematical formalism and computed results for energy‑balance hydrostatic models of the solar transition region. This paper examines the limitations of the hydrostatic and one‑dimensional assumptions used in such models. The authors incorporate diffusion by applying kinetic‑theory transport coefficients to compute helium departures from local ionization balance and assess the impact of coronal illumination on transition‑region structure and EUV line formation, including the He I 10830 Å line. The resulting helium spectra agree with observed hydrogen and helium line intensities and profiles, demonstrating that helium plays a significant role in energy transport. Published in The Astrophysical Journal (March 1993, DOI 10.1086/172443) with keywords such as chromosphere, helium, solar transition region, and diffusion.
view Abstract Citations (694) References (34) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Energy Balance in the Solar Transition Region. III. Helium Emission in Hydrostatic, Constant-Abundance Models with Diffusion Fontenla, J. M. ; Avrett, E. H. ; Loeser, R. Abstract In our previous papers we described the mathematical formalism and the computed results for energy-balance hydrostatic models of the solar transition region. In this paper we discuss in some detail the limitations of the hydrostatic and one-dimensional assumptions used. Then we analyze the determination of helium emission when diffusion is included. We use transport coefficients estimated from kinetic theory to determine the helium departures from local ionization balance. We calculate the helium spectra for each of our models and evaluate the role of helium in the energy transport. Also, we investigate the effects of coronal illumination on the structure of the transition region and upper chromosphere, and show how coronal illumination affects various EUV lines and the He I 10830 A line. Comparing with both absolute intensities and detailed line profiles, we show that our models are consistent not only with the observed hydrogen spectra but also with the available helium spectra. Publication: The Astrophysical Journal Pub Date: March 1993 DOI: 10.1086/172443 Bibcode: 1993ApJ...406..319F Keywords: Chromosphere; Emission Spectra; Helium; Solar Corona; Solar Radiation; Astronomical Models; Hydrostatics; Particle Diffusion; Solar Limb; Solar Physics; DIFFUSION; LINE: FORMATION; SUN: TRANSITION REGION; SUN: UV RADIATION full text sources ADS | Related Materials (2) Part 1: 1990ApJ...355..700F Part 2: 1991ApJ...377..712F