SCATTERING POLARIZATION OF THE Ca II IR TRIPLET FOR PROBING THE QUIET SOLAR CHROMOSPHERE

Manso Sainz, R

doi:10.1088/0004-637X/722/2/1416

Title: SCATTERING POLARIZATION OF THE Ca II IR TRIPLET FOR PROBING THE QUIET SOLAR CHROMOSPHERE

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Abstract

The chromosphere of the quiet Sun is a very important stellar atmospheric region whose thermal and magnetic structure we need to decipher in order to unlock new discoveries in solar and stellar physics. To this end, we need to identify and exploit observables sensitive to weak magnetic fields (B {approx}< 100 G) and to the presence of cool and hot gas in the bulk of the solar chromosphere. Here, we report on an investigation of the Hanle effect in two semi-empirical models of the quiet solar atmosphere with different chromospheric thermal structures. Our study reveals that the linear polarization profiles produced by scattering in the Ca II IR triplet have thermal and magnetic sensitivities potentially of great diagnostic value. The linear polarization in the 8498 A line shows a strong sensitivity to inclined magnetic fields with strengths between 0.001 and 10 G, while the emergent linear polarization in the 8542 A and 8662 A lines is mainly sensitive to magnetic fields with strengths between 0.001 and 0.1 G. The reason for this is that the scattering polarization of the 8542 A and 8662 A lines, unlike the 8498 A line, is controlled mainly by the Hanle effect in their (metastable)more »« less

Authors:: Manso Sainz, R

Publication Date:: Wed Oct 20 00:00:00 EDT 2010

OSTI Identifier:: 21464610

Resource Type:: Journal Article

Journal Name:: Astrophysical Journal

Additional Journal Information:: Journal Volume: 722; Journal Issue: 2; Other Information: DOI: 10.1088/0004-637X/722/2/1416; Journal ID: ISSN 0004-637X

Country of Publication:: United States

Language:: English

Subject:: 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; 79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; CHROMOSPHERE; MAGNETIC FIELD CONFIGURATIONS; MAGNETIC FIELDS; POLARIZATION; SUN; ATMOSPHERES; MAIN SEQUENCE STARS; SOLAR ATMOSPHERE; STARS; STELLAR ATMOSPHERES

Citation Formats


                    Manso Sainz, R, and Trujillo Bueno, J., E-mail: rsainz@iac.e, E-mail: jtb@iac.e. SCATTERING POLARIZATION OF THE Ca II IR TRIPLET FOR PROBING THE QUIET SOLAR CHROMOSPHERE.  United States: N. p., 2010. 
        Web.  doi:10.1088/0004-637X/722/2/1416.

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                    Manso Sainz, R, & Trujillo Bueno, J., E-mail: rsainz@iac.e, E-mail: jtb@iac.e. SCATTERING POLARIZATION OF THE Ca II IR TRIPLET FOR PROBING THE QUIET SOLAR CHROMOSPHERE.  United States.  https://doi.org/10.1088/0004-637X/722/2/1416

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                    Manso Sainz, R, and Trujillo Bueno, J., E-mail: rsainz@iac.e, E-mail: jtb@iac.e. 2010.  
        "SCATTERING POLARIZATION OF THE Ca II IR TRIPLET FOR PROBING THE QUIET SOLAR CHROMOSPHERE".  United States.  https://doi.org/10.1088/0004-637X/722/2/1416.

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@article{osti_21464610,

  title        = {SCATTERING POLARIZATION OF THE Ca II IR TRIPLET FOR PROBING THE QUIET SOLAR CHROMOSPHERE},

  author       = {Manso Sainz, R and Trujillo Bueno, J., E-mail: rsainz@iac.e, E-mail: jtb@iac.e},

  abstractNote = {The chromosphere of the quiet Sun is a very important stellar atmospheric region whose thermal and magnetic structure we need to decipher in order to unlock new discoveries in solar and stellar physics. To this end, we need to identify and exploit observables sensitive to weak magnetic fields (B {approx}< 100 G) and to the presence of cool and hot gas in the bulk of the solar chromosphere. Here, we report on an investigation of the Hanle effect in two semi-empirical models of the quiet solar atmosphere with different chromospheric thermal structures. Our study reveals that the linear polarization profiles produced by scattering in the Ca II IR triplet have thermal and magnetic sensitivities potentially of great diagnostic value. The linear polarization in the 8498 A line shows a strong sensitivity to inclined magnetic fields with strengths between 0.001 and 10 G, while the emergent linear polarization in the 8542 A and 8662 A lines is mainly sensitive to magnetic fields with strengths between 0.001 and 0.1 G. The reason for this is that the scattering polarization of the 8542 A and 8662 A lines, unlike the 8498 A line, is controlled mainly by the Hanle effect in their (metastable) lower levels. Therefore, in regions with magnetic strengths noticeably larger than 1 G, their Stokes Q and U profiles are sensitive only to the orientation of the magnetic field vector. We also find that for given magnetic field configurations the sign of the Q/I and U/I profiles of the 8542 A and 8662 A lines is the same in both atmospheric models, while the sign of the linear polarization profile of the 8498 A line turns out to be very sensitive to the thermal structure of the lower chromosphere. We suggest that spectropolarimetric observations providing information on the relative scattering polarization amplitudes of the Ca II IR triplet will be very useful to improve our empirical understanding of the thermal and magnetic structure of the quiet chromosphere.},

  doi          = {10.1088/0004-637X/722/2/1416},

  url          = {https://www.osti.gov/biblio/21464610},
  journal      = {Astrophysical Journal},

  issn         = {0004-637X},

  number       = 2,

  volume       = 722,

  place        = {United States},

  year         = {Wed Oct 20 00:00:00 EDT 2010},

  month        = {Wed Oct 20 00:00:00 EDT 2010}

}

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