Glauber calculations of polarization of Lyman-α resulting from e--H(1s) collisions

Abstract

The authors have calculated the polarization fraction of the Lyman- alpha radiation emitted in e^--H(1s) collisions using the Glauber, Born and various Vainshtein approximations, and have compared these predictions with observation. It is found that the Born, Glauber and all forms of the Vainshtein yield results which are very close to each other and to the data in the energy range 30 eVa<700 eV. The comparatively small differences between the various approximations are detailed in the text; also, the reason for the close agreement of the predicted polarization fractions-although the computed 1s-2p total and differential cross sections are not so close-is explained. With respect to the Glauber approximation, the importance of computing the phase integral along a direction perpendicular to the momentum transfer q at each value of q, is stressed.