Polarization of Resonance Lines in the Case of Partially Polarized Primary Radiation Sources

Abstract

The transfer of polarized radiation in a resonance line in a semi-infinite plane-parallel nonmagnetic atmosphere is examined. It is assumed that scattering takes place with complete frequency redistribution within the line and continuum absorption is taken into account. The primary radiation sources in the atmosphere are assumed to be partially polarized; here the function describing these sources is given by the product of a polynomial and an exponential of the optical depth. The Stokes vector of the emerging radiation is found using a general analytic theory of I ˆ -matrices (the I -matrix is a generalization of the scalar Chandrasekhar H-function). It is shown that the Stokes vector of the radiation emerging from an atmosphere in which primary sources of this form are distributed can be expressed in terms of the solution of a single, so-called standard problem.