Polarization Spectroscopy in Astrophysics
The polarization of radiation from the outer part of the solar atmosphere has been under continuous study for many years /85, 86/. The polarization of radiation coming from the solar photosphere is used daily by Solar Observatories all around the world to measure the spatial distribution of the solar photospheric magnetic field of solar active regions. During solar eclipses and with devoted instruments, where the radiation from the solar disk is occulted in order to allow observations of the much weaker emission from the low corona, the polarization of the radiation from the corona and from external concentration of neutral gas (prominences) is observed and studied. Using the most simple and straightforward model of Thomson scattering of light from the photosphere by free electrons and the theory of resonant scattering by free atoms and ions, the observations of the continuum and line spectra of the corona provide information on physical conditions in the solar corona. More recently, linear line polarization generated by anisotropies in the collisional excitation conditions of atomic species has been observed during solar flares, providing additional information on particle beams.
KeywordsSolar Flare Linear Polarization Solar Corona Polarization Fraction Velocity Distribution Function
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