Spectropolarimetric capabilities of Ca ii 8542 Å line

Noda, C. Quintero; Shimizu, Toshifumi; Rodríguez, J. de la Cruz; Katsukawa, Y.; Ichimoto, Kiyoshi; Anan, Tetsu; Suematsu, Y.

doi:10.1093/mnras/stw867

Cited by 60 publications

(60 citation statements)

References 44 publications

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“…The Ca II infrared (IR) triplet lines are well suited for flare diagnostics due to their good sensitivity to physical parameters, including magnetic field, in the solar photosphere and chromosphere (Pietarila et al 2007;Cauzzi et al 2008;de la Cruz Rodríguez et al 2012;Quintero Noda et al 2016). Furthermore, calcium is singly ionized under typical chromospheric conditions, with negligible nonequilibrium and partial redistribution effects for the Ca II IR lines (Uitenbroek 1989;Wedemeyer-Böhm & Carlsson 2011), making their modeling and interpretation of the observations more straightforward.…”

Section: Introductionmentioning

confidence: 99%

Spectropolarimetric Inversions of the Ca ii 8542 Å Line in an M-class Solar Flare

Kuridze

Henriques

Mathioudakis

et al. 2018

ApJ

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We study the M1.9 class solar flare SOL2015-09-27T10:40 UT using high-resolution full-Stokes imaging spectropolarimetry of the Ca ii 8542 Å line obtained with the CRISP imaging spectropolarimeter at the Swedish 1-m Solar Telescope. Spectropolarimetric inversions using the non-LTE code NICOLE are used to construct semi-empirical models of the flaring atmosphere to investigate the structure and evolution of the flare temperature and magnetic field. A comparison of the temperature stratification in flaring and non-flaring areas reveals strong heating of the flare ribbon during the flare peak. The polarization signals of the ribbon in the chromosphere during the flare maximum become stronger when compared to its surroundings and to pre-and post-flare profiles. Furthermore, a comparison of the response functions to perturbations in the line-of-sight magnetic field and temperature in flaring and non-flaring atmospheres shows that during the flare the Ca ii 8542 Å line is more sensitive to the lower atmosphere where the magnetic field is expected to be stronger. The chromospheric magnetic field was also determined with the weak-field approximation which led to results similar to those obtained with the NICOLE inversions.

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Section: Introductionmentioning

confidence: 99%

Spectropolarimetric Inversions of the Ca ii 8542 Å Line in an M-class Solar Flare

Kuridze

Henriques

Mathioudakis

et al. 2018

ApJ

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“…For example, Hinode/SP was strongly supported by ASP (Elmore et al 1992) observations and SDO/HMI benefited from groundbased observations but also from specific supporting works as Norton et al (2006). We performed a similar study in Quintero Noda et al (2016) aiming to support future misc 2016 The Authors sions with chromospheric polarimetry as the main target, for instance, Solar-C (Katsukawa & Solar-C Working Groups 2011;Katsukawa et al 2012;Watanabe 2014;Suematsu & Solar-C Working Group 2016). We concluded that the Ca ii 8542Å is a unique spectral line that is sensitive to a large range of heights, from the photosphere to the chromosphere (see Figure 4 and 6 of the mentioned work).…”

Section: Introductionmentioning

confidence: 72%

“…We have selected a small fragment of the simulated snapshot, see Figure 5. This fragment is different than the one used in Quintero Noda et al (2016), i.e. it is three times larger and contains most of the magnetic patch located on the right side of the original field of view (see Figure 2 of Carlsson et al (2016)).…”

Section: Synthesis Of Stokes Profiles Using a Realistic 3d Modelmentioning

confidence: 98%

Chromospheric polarimetry through multiline observations of the 850-nm spectral region

Noda¹,

Shimizu²,

Katsukawa³

et al. 2016

Mon. Not. R. Astron. Soc.

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Future solar missions and ground-based telescopes aim to understand the magnetism of the solar chromosphere. We performed a supporting study in Quintero Noda et al. (2016) focused on the infrared Ca ii 8542Å line and we concluded that is one of the best candidates because it is sensitive to a large range of atmospheric heights, from the photosphere to the middle chromosphere. However, we believe that it is worth to try improving the results produced by this line observing additional spectral lines. In that regard, we examined the neighbour solar spectrum looking for spectral lines that could increase the sensitivity to the atmospheric parameters. Interestingly, we discovered several photospheric lines that greatly improve the photospheric sensitivity to the magnetic field vector. Moreover, they are located close to a second chromospheric line that also belongs to the Ca ii infrared triplet, i.e. the Ca ii 8498Å line, and enhances the sensitivity to the atmospheric parameters at chromospheric layers. We conclude that the lines in the vicinity of the Ca ii 8542Å line not only increase its sensitivity to the atmospheric parameters at all layers, but also they constitute an excellent spectral window for chromospheric polarimetry.

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“…Additionally, and according to Quintero Noda et al (2016), these wing signals do still have a strong chromospheric contribution, with the response functions peaking very high in the atmosphere.…”

Section: Polarimetric Datamentioning

confidence: 87%

Inference of the chromospheric magnetic field orientation in the Ca ii 8542 Å line fibrils

Ramos

Rodríguez

González

et al. 2017

A&A

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Context. Solar chromospheric fibrils, as observed in the core of strong chromospheric spectral lines, extend from photospheric field concentrations suggesting that they trace magnetic field lines. These images have been historically used as proxies of magnetic fields for many purposes. Aims. Use statistical analysis to test whether the association between fibrils and magnetic field lines is justified. Methods. We use a Bayesian hierarchical model to analyze several tens of thousands of pixels in spectro-polarimetric chromospheric images of penumbrae and chromospheric fibrils. We compare the alignment between the field azimuth inferred from the linear polarization signals through the transverse Zeeman effect and the direction of the fibrils in the image. Results. We conclude that, in the analyzed fields of view, fibrils are often well aligned with the magnetic field azimuth. Despite this alignment, the analysis also shows that there is a non-negligible dispersion. In penumbral filaments, we find a dispersion with a standard deviation of ∼ 16 • , while this dispersion goes up to ∼ 34 • in less magnetized regions.

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Spectropolarimetric capabilities of Ca ii 8542 Å line

Cited by 60 publications

References 44 publications

Spectropolarimetric Inversions of the Ca ii 8542 Å Line in an M-class Solar Flare

Spectropolarimetric Inversions of the Ca ii 8542 Å Line in an M-class Solar Flare

Chromospheric polarimetry through multiline observations of the 850-nm spectral region

Inference of the chromospheric magnetic field orientation in the Ca ii 8542 Å line fibrils

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