TIC: A Stokes Inversion Code for Scattering Polarization with Partial Frequency Redistribution and Arbitrary Magnetic Fields

Li, Hao; Alemán, T. del Pino; Bueno, J. Trujillo; Casini, R.

doi:10.3847/1538-4357/ac745c

Cited by 16 publications

(17 citation statements)

References 41 publications

(34 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…To this end, the regularization included in he4 allows the inversion code FIRTEZ-dz to choose between either of the aforementioned situations based on whether the fit to the synthetic Stokes profiles truly improves when large z variations are included; otherwise, it favors smoother solutions along the z direction. Other codes capable of carrying out Stokes inversion with vertical regularization are STiC (de la Cruz Rodríguez et al 2019) and TIC (Li et al 2022).…”

Section: Effect Of Vertical Tikhonov Regularization (He4)mentioning

confidence: 99%

Combining magneto-hydrostatic constraints with Stokes profiles inversions

Borrero

Yabar

2023

A&A

View full text Add to dashboard Cite

Context. Electric currents play an important role in the energy balance of the plasma in the solar atmosphere. They are also indicative of non-potential magnetic fields and magnetic reconnection. Unfortunately, the direct measuring of electric currents has traditionally been riddled with inaccuracies. Aims. We study how accurately we can infer electric currents under different scenarios. Methods. We carry out increasingly complex inversions of the radiative transfer equation for polarized light applied to Stokes profiles synthesized from radiative three-dimensional magnetohydrodynamic (MHD) simulations. The inversion yields the magnetic field vector, B, from which the electric current density, j, is derived by applying Ampere's law. Results. We find that the retrieval of the electric current density is only slightly affected by photon noise or spectral resolution. However, the retrieval steadily improves as the Stokes inversion becomes increasingly elaborated. In the least complex case (a Milne-Eddington-like inversion applied to a single spectral region), it is possible to determine the individual components of the electric current density ( j x , j y , j z ) with an accuracy of σ = 0.90 − 1.00 dex, whereas the modulus ( j ) can only be determined with σ = 0.75 dex. In the most complicated case (with multiple spectral regions, a large number of nodes, Tikhonov vertical regularization, and magnetohydrostatic equilibrium), these numbers improve to σ = 0.70 − 0.75 dex for the individual components and σ = 0.5 dex for the modulus. Moreover, in regions where the magnetic field is above 300 gauss, j can be inferred with an accuracy of σ = 0.3 dex. In general, the x and y components of the electric current density are retrieved slightly better than the z component. In addition, the modulus of the electric current density is the best retrieved parameter of all, and thus it can potentially be used to detect regions of enhanced Joule heating. Conclusions. The fact that the accuracy does not worsen with decreasing spectral resolution or increasing photon noise, and instead increases as the Stokes inversion complexity grows, suggests that the main source of errors in the determination of electric currents is the lack of realism in the inversion model employed to determine variations in the magnetic field along the line of sight at scales smaller than the photon mean-free path, along with the intrinsic limitations of the model due to radiative transfer effects.

show abstract

Section: Effect Of Vertical Tikhonov Regularization (He4)mentioning

confidence: 99%

Combining magneto-hydrostatic constraints with Stokes profiles inversions

Borrero

Yabar

2023

A&A

View full text Add to dashboard Cite

show abstract

“…Multi-line non-local thermodynamic equilibrium (NLTE) inversion codes can be used to reconstruct the physical parameters of a depth-stratified model atmosphere of the photosphere and chromosphere (e.g. Socas-Navarro et al 2015;Milić & van Noort 2018;de la Cruz Rodríguez et al 2019;Ruiz Cobo et al 2022;Li et al 2022). The radiative losses must be estimated in the main chromospheric coolers originating from hydrogen, magnesium and calcium atoms (e.g.…”

Section: Chromospheric Dynamics Magnetism and Heatingmentioning

confidence: 99%

The European Solar Telescope

Noda

Schlichenmaier

Rubio

et al. 2022

A&A

Self Cite

View full text Add to dashboard Cite

The European Solar Telescope (EST) is a project aimed at studying the magnetic connectivity of the solar atmosphere, from the deep photosphere to the upper chromosphere. Its design combines the knowledge and expertise gathered by the European solar physics community during the construction and operation of state-of-the-art solar telescopes operating in visible and near-infrared wavelengths: the Swedish 1m Solar Telescope, the German Vacuum Tower Telescope and GREGOR, the French Télescope Héliographique pour l’Étude du Magnétisme et des Instabilités Solaires, and the Dutch Open Telescope. With its 4.2 m primary mirror and an open configuration, EST will become the most powerful European ground-based facility to study the Sun in the coming decades in the visible and near-infrared bands. EST uses the most innovative technological advances: the first adaptive secondary mirror ever used in a solar telescope, a complex multi-conjugate adaptive optics with deformable mirrors that form part of the optical design in a natural way, a polarimetrically compensated telescope design that eliminates the complex temporal variation and wavelength dependence of the telescope Mueller matrix, and an instrument suite containing several (etalon-based) tunable imaging spectropolarimeters and several integral field unit spectropolarimeters. This publication summarises some fundamental science questions that can be addressed with the telescope, together with a complete description of its major subsystems.

show abstract

“…The scale of calculations needed to supplement Mg + work increases far more than quadratically than the square of the number of levels (such as five for Ca + , many more for Fe + ), owing to the need to solve for off-diagonal elements of the atomic density matrices in statistical equilibrium (Landi degl'Innocenti & Landolfi 2004). Such large-scale calculations are not currently routine, but are being implemented (e.g., Li et al 2022).…”

Section: Mg II Versus Ca Iimentioning

confidence: 99%

Optimal Spectral Lines for Measuring Chromospheric Magnetic Fields

Judge

Bryans

Casini

et al. 2022

ApJ

Self Cite

View full text Add to dashboard Cite

This paper identifies spectral lines from X-ray to IR wavelengths which are optimally suited to measuring vector magnetic fields as high as possible in the solar atmosphere. Instrumental and Earth's atmospheric properties, as well as solar abundances, atmospheric properties, and elementary atomic physics are considered without bias toward particular wavelengths or diagnostic techniques. While narrowly focused investigations of individual lines have been reported in detail, no assessment of the comparative merits of all lines has ever been published. Although in the UV, on balance the Mg+ h and k lines near 2800 Å are optimally suited to polarimetry of plasma near the base of the solar corona. This result was unanticipated, given that longer-wavelength lines offer greater sensitivity to the Zeeman effect. While these lines sample optical depths photosphere to the coronal base, we argue that cores of multiple spectral lines provide a far more discriminating probe of magnetic structure as a function of optical depth than the core and inner wings of a strong line. Thus, together with many chromospheric lines of Fe+ between 2585 Å and the h line at 2803 Å, this UV region promises new discoveries concerning how the magnetic fields emerge, heat, and accelerate plasma as they battle to dominate the force and energy balance within the poorly understood chromosphere.

show abstract

TIC: A Stokes Inversion Code for Scattering Polarization with Partial Frequency Redistribution and Arbitrary Magnetic Fields

Cited by 16 publications

References 41 publications

Combining magneto-hydrostatic constraints with Stokes profiles inversions

Combining magneto-hydrostatic constraints with Stokes profiles inversions

The European Solar Telescope

Optimal Spectral Lines for Measuring Chromospheric Magnetic Fields

Contact Info

Product

Resources

About