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Scattering Polarization in the Chromosphere

  • C. U. Keller
  • N. R. SheeleyJr.
Part of the Astrophysics and Space Science Library book series (ASSL, volume 243)

Abstract

Scattering polarization from the photosphere observed close to the solar limb has recently become of interest to study turbulent magnetic fields, abundances, and radiative transfer effects. We extend these studies by measuring the scattering polarization off the limb, i.e. in the chromosphere. However, instrumental effects are much more pronounced and more complicated than those affecting on-disk measurements. In particular, scattered light from the telescope mirrors leads to a new type of instrumental polarization that we describe in detail. The differences between the linearly polarized spectra on the disk and off the limb are often very substantial. Here we show the profiles of Hei D3, the OI triplet at 777 nm, and the Nai D lines. The change in the latter is in reasonable agreement with the recent modeling efforts of atomic polarization in the lower level by Landi Degl’Innocenti (1998).

Key words

scattering polarization chromosphere observations 

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Copyright information

© Springer Science+Business Media Dordrecht 1999

Authors and Affiliations

  • C. U. Keller
    • 1
  • N. R. SheeleyJr.
    • 2
  1. 1.National Solar ObservatoryTucsonUSA
  2. 2.Naval Research LaboratoryWashingtonUSA

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