LONG-WAVELENGTH RADIATION ALONG A STRAIGHT-SECTION AXIS IN AN ELECTRON STORAGE-RING

The long-wavelength radiation emitted along a straight-section axis of an electron storage ring is considered. A bending magnet at the begin ning or end of a straight section produces cylindrically-symmetric ''e dge'' radiation with radial polarization, collimated in a cone with op ening angle of similar to 1/gamma, where gamma is the relativistic mas s factor. A small deflection from a steering magnet or misaligned quad rupole results in ''kicker'' radiation, also collimated with an openin g angle of similar to 1/gamma, for which the photon flux is proportion al to the square of the deflection angle. Intermediate deflection angl es of similar to 1/gamma produce a photon flux comparable to edge radi ation. Downstream of a typical straight section which includes entranc e and exit bending magnet edges, wiggler or undulator, and miscellaneo us steering kicks comparable to 1/gamma, the long-wavelength radiation is a superposition from numerous sources, each producing a comparable photon flux with opening angle of similar to 1/gamma.