J/A+A/688/A56 Quiet-Sun photosphere and lower chromosphere (Borrero+, 2024)
One-dimensional, geometrically stratified semi-empirical models of the
quiet-Sun photosphere and lower chromosphere.
Borrero J.M., Milic I., Pastor Yabar A., Kaithakkal A.J.,
de la Cruz Rodriguez J.
<Astron. Astrophys. 688, A56 (2024)>
=2024A&A...688A..56B 2024A&A...688A..56B
ADC_Keywords: Sun
Keywords: magnetohydrodynamics (MHD) - polarization - radiative transfer -
Sun: atmosphere - Sun: chromosphere - Sun: granulation -
Abstract:
One-dimensional, semi-empirical models of the solar atmosphere are
widely employed in numerous contexts within solar physics, ranging
from the determination of element abundances and atomic parameters to
studies of the solar irradiance and from Stokes inversions to coronal
extrapolations. These models provide the physical parameters (i.e.
temperature, gas pressure, etc.) in the solar atmosphere as a function
of the continuum optical depth τc. The transformation to the
geometrical z scale (i.e. vertical coordinate) is provided via
vertical hydrostatic equilibrium.
Our aim is to provide updated, one-dimensional, semi-empirical models
of the solar atmosphere as a function of z, but employing the more
general case of three-dimensional magneto-hydrostatic equilibrium
(MHS) instead of vertical hydrostatic equilibrium (HE).
We employed a recently developed Stokes inversion code that, along
with non-local thermodynamic equilibrium effects, considers MHS
instead of HE. This code is applied to spatially and temporally
resolved spectropolarimetric observations of the quiet Sun obtained
with the CRISP instrument attached to the Swedish Solar Telescope.
We provide average models for granules, intergranules, dark magnetic
elements, and overall quiet-Sun as a function of both τc and z
from the photosphere to the lower chromosphere.
We demonstrate that, in these quiet-Sun models, the effect of
considering MHS instead of HE is negligible. However, employing MHS
increases the consistency of the inversion results before averaging.
We surmise that in regions with stronger magnetic fields (i.e. pores,
sunspots, network) the benefits of employing the magneto-hydrostatic
approximation will be much more palpable.
Description:
We present several one-dimensional semi-empirical models of the solar
photosphere and lower chromosphere in the quiet Sun. The models are
prescribed both the optical depth scale and the z-scale. They were
obtained via the inversion of Stokes profiles in the FeI line at
617.3nm and CaII line at 854.2nm. The Stokes profiles were inverted
using the FIRTEZ-dz code assuming LTE for FeI but treating CaII
under non-LTE. The z-scale was obtained under the assumption of
magneto-hydrostatic equilibrium. The observed Stokes profiles were
recorded with the CRISP instrument attached to the 1-m Solar Swedish
Telescope. Four models are provided in total: average quiet Sun,
average granular models, average intergranular models, and average
dark magnetic element model.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 113 128 Average model for the entire quiet Sun
tablea2.dat 113 128 Average model only granular regions
tablea3.dat 113 128 Average model only intergranular regions
tablea4.dat 113 128 Average model dark magnetic element
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Byte-by-byte Description of file: tablea[1234].dat
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Bytes Format Units Label Explanations
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2- 5 I4 km z Vertical direction
9- 14 F6.3 [-] tau logarithm of the optical depth at 500nm
(in (c)- unit)
17- 23 F7.2 K T Temperature
27- 32 F6.2 gauss Bz Vertical component of the magnetic field
37- 41 F5.2 gauss Bh Horizontal component of the magnetic field
46- 51 F6.3 km/s vz Vertical component of the velocity
55- 64 E10.4 dyn/cm2 Pg Gas pressure
68- 77 E10.4 g/s2/cm2 rho*g Gravity force
79- 90 E12.4 g/s2/cm2 Lz Vertical component of the Lorentz force
92-101 E10.4 cm-3 nelec Electron density in non-LTE
104-113 E10.4 cm-3 nh Hydrogen density
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Acknowledgements:
Juan Manuel Borrero, borrero(at)leibniz-kis.de
(End) Juan Manuel Borrero [KIS, Germany], Patricia Vannier [CDS] 10-Apr-2024