Abstract

For zero electron drift velocity, the corrected version¹ of Vachaspati's classical cross sections¹-² deviates strongly from a semi–classical one by Ehlotzky³ and from an unpublished quantum electrodynamical cross section by Jafarpour.⁴ Therefore, the cross section is recalculated within classical electrodynamics, which suffices for the experimental configurations in question.⁵ This classical cross section, derivable more simply and with fewer approximations than the semi–classical one, nevertheless agrees perfectly with Elotzky's result³ for all harmonics, but only to some extent with Vachaspati's earlier version² of the classical second harmonic cross section, and not at all with his corrected one,¹ nor with Jafarpour's quantum electrodynamical one.⁴ Moreover, it also incorporates relativistic Thomson scattering as envisaged by McDonald.⁶

© 1988 Optical Society of America