Long-wavelength edge radiation in an electron storage ring

Abstract

The edge radiation emitted from a bending magnet edge in an electron storage ring is considered for wavelengths sufficiently long that the spatial extent of the magnet edge may be neglected. For a typical electron storage ring with energy ⩾800 MeV, this “zero edge length” model applies to the infrared region. The far-field edge radiation is radially polarized, directed in a cylindrically-symmetric hollow cone along the straight-section axis with peak intensity at an opening angle of 1/γ, where γ is the relativistic mass factor. At the wavelength, λ, the near field occurs at observer distance, R, less than λγ2. The near-field edge radiation is also radially polarized, forming a hollow cylindrical distribution with peak intensity at a distance (Rλ)1/2 from the straight-section axis.