Contribution and response functions for Caii lines in different atmospheric models

Grigoryeva, S. A.; Turova, I. P.; Teplitskaya, R. B.

doi:10.1007/bf00146695

Cited by 10 publications

(3 citation statements)

References 11 publications

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“…After a few A&A 549, A24 (2013) attempts for a direct analysis of Ca ii spectra in the quiet Sun (QS) (Liu & Skumanich 1974) or active regions (e.g., Teplitskaja & Efendieva 1975) in the 70 s and 80 s, the topic has not received much attention in recent years. Apart from the inversion code for Ca ii K spectra described in Rouppe van der Voort (2002) that is based on Shine & Linsky (1974a) and the manual inversion method for the line wings of Ca ii H and K used in Sheminova et al (2005) and Sheminova (2012), only the group led by Prof. Teplitskaya seems to have continued with the development of analysis and/or inversion tools for Ca ii H and K (Grigoryeva et al 1991(Grigoryeva et al , 2000). …”

Section: Introductionmentioning

confidence: 99%

The energy of waves in the photosphere and lower chromosphere

Beck

Rezaei

Puschmann

2012

A&A

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Context. The Ca ii H line is one of the strongest lines in the solar spectrum, and it provides continuous information on the solar atmosphere from the photosphere to the lower chromosphere.Aims. We describe an inversion approach that reproduces observed Ca ii H spectra by assuming local thermal equilibrium (LTE). Methods. We developed an inversion strategy based on the SIR code that reproduces Ca ii H spectra in the LTE approximation. The approach uses a two-step procedure with an archive of pre-calculated spectra to fit the line core and a subsequent iterative modification to improve the fit mainly in the line wing. Simultaneous spectra in the 630 nm range can optionally be used to fix the continuum temperature. The method retrieves one-dimensional (1D) temperature stratifications while neglecting lateral radiative transport. Lineof-sight velocities are included post facto with an empirical approach.Results. An archive of about 300 000 pre-calculated spectra is more than sufficient to reproduce the line core of observed Ca ii H spectra both in the quiet Sun and in active regions. The subsequent iterative adjustment of the thermodynamical stratification matches observed and best-fit spectra to a level of about 0.5% of I c in the line wing and about 1% of I c in the line core. Conclusions. The successful application of the LTE inversion strategy suggests that inversion schemes based on pre-calculated spectra allow a reliable and relatively fast retrieval of solar properties from observed chromospheric spectra. The approach can be easily extended to a 1D non-LTE (NLTE) case by a simple exchange of the pre-calculated archive spectra. Using synthetic NLTE spectra from numerical three-dimensional (3D) simulations instead will finally allow one to extend the approach from the static 1D-case to dynamical atmosphere models, including the complete 3D radiative transport.

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Section: Introductionmentioning

confidence: 99%

The energy of waves in the photosphere and lower chromosphere

Beck

Rezaei

Puschmann

2012

A&A

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“…One can --'""l-"""q"'"""l""'""q"'"'"'l"'""" easily conceive that such procedure (sometimes used, e.g., Wittmann 1974, and for non-polarized light analyses, e.g., Grigoryeva, Turova, & Teplitskaya 1991) is enormously tedious and precludes most authors from employing it. If we just deal with a given quantity, xk, and 5xk(r) = 5(r -To) (Dirac's delta, whose physical meaning would be a perturbation in a small interval around r0), then t~I = Rk(r0).…”

Section: Evaluation Of the Stokes Profiles Sensitivitiesmentioning

confidence: 99%

Stokes profiles inversion techniques

Iniesta

Cobo

1996

Sol Phys

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Inversion techniques of the radiative transfer equation for polarized light are presented as one of the best current procedures to infer the vector magnetic field, as well as other quantities governing the physical state of the atmospheric layers that photons are coming from. Several characteristics of the various available inversion procedures are pointed out. They are mostly based on the diagnostic contents of the spectral lines as well as on the main hypotheses assumed in these procedures. In particular, the role of gradients in the atmospheric quantities is emphasized as of paramount importance in any diagnostic analysis and, hence, in any interpretation of inversion results.

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“…After a few attempts for a direct analysis of Ca ii spectra in quiet Sun (QS) (Liu & Skumanich 1974) or active regions (e.g., Teplitskaja & Efendieva 1975) in the 70's and 80's, the topic has not received much attention in the recent years. Apart from the inversion code for Ca ii K spectra described in Rouppe van der Voort (2002) that is based on Shine & Linsky (1974a) and the manual inversion method for the line wings of Ca ii H and K used in Sheminova et al (2005) and Sheminova (2012), only the group led by Prof. Teplitskaya seems to have continued with the development of analysis and/or inversion tools for Ca ii H and K (Grigoryeva et al 1991(Grigoryeva et al , 2000(Grigoryeva et al , 2009.…”

Section: Introductionmentioning

confidence: 99%

The energy of waves in the photosphere and lower chromosphere: III. Inversion setup for Ca II H spectra in local thermal equilibrium

Beck,

Rezaei,

Puschmann

2012

Preprint

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Context. The Ca ii H line is one of the strongest lines in the solar spectrum and provides continuous information on the solar atmosphere from the photosphere to the lower chromosphere. Aims. We describe an inversion approach that reproduces observed Ca ii H spectra assuming local thermal equilibrium (LTE). Methods. We developed an inversion strategy based on the SIR code that reproduces Ca ii H spectra in the LTE approximation. The approach uses a two-step procedure with an archive of pre-calculated spectra to fit the line core and a subsequent iterative modification to improve the fit mainly in the line wing. Simultaneous spectra in the 630 nm range can optionally be used to fix the continuum temperature. The method retrieves one-dimensional (1D) temperature stratifications neglecting lateral radiative transport. Line-of-sight velocities are included post-facto by an empirical approach.Results. An archive of about 300.000 pre-calculated spectra is more than sufficient to reproduce the line core of observed Ca ii H spectra both in quiet Sun and in active regions. The subsequent iterative adjustment of the thermodynamical stratification matches observed and best-fit spectra to a level of about 0.5 % of I c in the line wing and about 1 % of I c in the line core. Conclusions. The successful application of the LTE inversion strategy suggests that inversion schemes based on pre-calculated spectra allow one a reliable and relatively fast retrieval of solar properties from observed chromospheric spectra. The approach can be easily extended to an 1D non-LTE (NLTE) case by a simple exchange of the pre-calculated archive spectra. Using synthetic NLTE spectra from numerical three-dimensional (3D) simulations instead will finally allow one to extend the approach from the static 1D-case to dynamical atmosphere models including the complete 3D radiative transport.

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Contribution and response functions for Caii lines in different atmospheric models

Cited by 10 publications

References 11 publications

The energy of waves in the photosphere and lower chromosphere

The energy of waves in the photosphere and lower chromosphere

Stokes profiles inversion techniques

The energy of waves in the photosphere and lower chromosphere: III. Inversion setup for Ca II H spectra in local thermal equilibrium

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