Modelling broadband polarisation in sunspots
نویسنده
چکیده
The eeect of line overlap (blending) on broadband linear (NLP) and circular (NCP) polarisation in spectra of solar magnetic regions , especially sunspot umbrae, is explored in a systematic way, employing spectrum synthesis in polarised light on a grand scale over thousands of Angstrr oms. An extensive grid of theoretical Stokes IQU V spectra allows the discussion of the dependence of NLP and NCP on atmospheric parameters such as temperature, microturbulence, magnetic eld strength and direction. NCP, resulting from incomplete cancellation of excess circular polarisation originating in blends (a small-number statistical eeect), can attain observable values even in perfectly static atmospheres.
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