Incoherent Undulator Radiation

Abstract

The spontaneous synchrotron radiation produced by individual electrons executing undulatory trajectories in a magnetostatic field is incoherent and is the radiation mechanism used in synchrotron light sources. The magnetostatic fields in these devices are formaBy identical to those employed in free-electron lasers but are commonly referred to as undulators rather than wigglers. The reason for this is that electron synchrotrons produce high-energy electron beams which permit the use of extremely long-period undulations. The use of long-period undulations makes possible the production of relatively large-amplitude magnetostatic fields which are required to ensure the production of a relatively high radiation intensity from this incoherent mechanism. In contrast, since the free-electron laser relies on a coherent emission process, the wiggler magnets employed can be of shorter periods and lower amplitudes. However, incoherent synchrotron radiation is produced in free-electron lasers as well [[1]–[5]].