Fast inversion of solar Ca II spectra

Abstract

We present a fast (<< 1 s per profile) inversion code for solar Ca II lines. The code uses an archive of spectra that are synthesized prior to the inversion under the assumption of local thermodynamic equilibrium (LTE). We show that it can be successfully applied to spectrograph data or more sparsely sampled spectra from two-dimensional spectrometers. From a comparison to a non-LTE inversion of the same set of spectra, we derive a first-order non-LTE correction to the temperature stratifications derived in the LTE approach. The correction factor is close to unity up to log tau ~ -3 and increases to values of 2.5 and 4 at log tau = -6 in the quiet Sun and the umbra, respectively.

8 pages, 10 figures, accepted for publication in ApJ; version updated for an error in the references

References in corpus (12)

• Advanced Forward Modeling and Inversion of Stokes Profiles Resulting from the Joint Action of the Hanle and Zeeman Effects
• Spatially coupled inversion of spectro-polarimetric image data I: Method and first results
• Physical Properties of a Sunspot Chromosphere with Umbral Flashes
• Non-local thermodynamic equilibrium inversions from a 3D MHD chromospheric model
• The solar chromosphere at high resolution with IBIS: III. Comparison of Ca II K and Ca II 854.2 nm imaging
• Comparison of inversion codes for polarized line formation in MHD simulations. I. Milne-Eddington codes
• The energy of waves in the photosphere and lower chromosphere: IV. Inversion results of Ca II H spectra
• The energy of waves in the photosphere and lower chromosphere: III. Inversion setup for Ca II H spectra in local thermal equilibrium
• Model selection for spectro-polarimetric inversions
• A three-dimensional view of the thermal structure in a super-penumbral canopy
• The energy of waves in the photosphere and lower chromosphere: II. Intensity statistics
• Improved search of PCA databases for spectro-polarimetric inversion

Cited by in corpus (17)

• Alfvén Wave Dissipation in the Solar Chromosphere
• Waves in the lower solar atmosphere: the dawn of next-generation solar telescopes
• The Magnetic Response of the Solar Atmosphere to Umbral Flashes
• A new MHD-assisted Stokes inversion technique
• Spectroscopic inversions of the Ca ii 8542 Å line in a C-class solar flare
• RADYNVERSION: Learning to Invert a Solar Flare Atmosphere with Invertible Neural Networks
• Heating of the solar chromosphere in a sunspot light bridge by electric currents
• The New 2018 Version of the Meudon Spectroheliograph
• 2D non-LTE modelling of a filament observed in the H_alpha line with the DST/IBIS spectropolarimeter
• Accurately constraining velocity information from spectral imaging observations using machine learning techniques
• Fast Inversion of Solar Ca II Spectra in Non-Local Thermodynamic Equilibrium
• The formation of an atypical sunspot light bridge as a result of large-scale flux emergence
• Magnetic Properties and Flow Angle of the Inverse Evershed Flow at Its Downflow Points
• Structure of sunspot light bridges in the chromosphere and transition region
• The magnetic topology of the inverse Evershed flow
• On the effect of oscillatory phenomena on Stokes inversion results
• High-resolution Observations of Halpha Spectra with a Subtractive Double Pass