Radiation transfer through a model sunspot.
Abstract
We present a cylindrically symmetric model for a sunspot atmosphere using the similarity principle of Schlüter and Temesvary for the magnetic field configuration. The equations of magnetostatic equilibrium are used, augmented by a radial Evershed flow. The LTE radiative transfer equations for the Stokes vector were solved under a variety of conditions for a ray emerging from a typical penumbral point. The contribution from isolated lines to the broadband circular polarization in sunspot penumbrae is evaluated using a more realistic model sunspot atmosphere than has hitherto been considered. Results indicate that the inclusion of a velocity field along B is unable to give a net circular polarization of sufficient magnitude, although the variation with the angle between the line-of-sight and B is in qualitative agreement with observations. The corresponding results for the net linear polarization are satisfactory.
- Publication:
-
Solar Physics
- Pub Date:
- September 1979
- DOI:
- 10.1007/BF00174528
- Bibcode:
- 1979SoPh...63..221L
- Keywords:
-
- Atmospheric Models;
- Polarization Characteristics;
- Radiative Transfer;
- Stellar Models;
- Sunspots;
- Line Spectra;
- Penumbras;
- Photosphere;
- Solar Spectra;
- Thermodynamic Equilibrium;
- Solar Physics;
- Radiation Transfer;
- Qualitative Agreement;
- Linear Polarization;
- Circular Polarization;
- Transfer Equation;
- Radiative Transfer:Sunspots;
- Sunspots:Models