Standard wiggler magnets

Abstract

Interest in wiggler magnets (a close sequence of transverse fields with alternating polarity) to extend and enhance the spectrum of synchrotron radiation from electron storage rings has increased significantly during the past few years. In this paper we consider standard wigglers i.e. wigglers in which interference effects on the spectrum of synchrotron radiation are not important. In standard wigglers the spectrum of synchrotron radiation has the same general shape as the spectrum from ring bending magnets. However, the critical energy of the wiggler spectrum may be different. The critical energy of the wiggler spectrum is given by: ε CW = ϵ CB B W B B , where ϵ CB is the critical energy from the bending magnets and B W and B B are the magnetic field strengths of the wiggler magnet and bending magnets respectively. Since most electron storage rings operate with relatively low bending magnet fields ( B B≲12 kG), even a modest wiggler magnet field (≈ 18 kG) can significantly increase the critical energy. Such magnets are planned for ADONE and SPEAR. Higher field ≈ 45 kG) superconducting magnets are planned at Daresbury and Brookhaven to produce due to the superposition of the radiation from the individual poles. Wiggler designs are discussed the spectrum is produced due to the superposition of the radiation from the individual poles. Wiggler designs are discussed as well as the effect of wigglers on the synchrotron radiation spectrum and on the operation of storage rings.