V. I. R. Niculescu, S. Micloş, D. Savastru, A. Popescu, L. Şandru, Magnetic field Wiggy-Chain undulator, Optoelectron. Adv. Mater. – Rapid Comm., 4/12 (2010) 2154 – 2156.


Title: Magnetic field Wiggy-Chain undulator

Abstract: The phenomenon of tuned coherent radiation in free-electron lasers is given by undulator - the FEL main component. The radiation is issued by a relativistic electron beam injected in a periodic magnetic field generated by spatially periodic structures made up of permanent magnets or currents. Important difficulties in mathematical evaluation of the magnetic field components occur when using circular undulator cross section. Therefore a substitution of the circular cross section by a polygonal cross section, easier mathematically treatable, is desirable. In this paper a hexagonal cross section was chosen. Each wire of the stack (a frame) is made up of two chains that are connected alternating to the chains of the next frame. Eventually, in the last frame the two chains are connected to each other, closing the circuit. In a frame, each chain has a loop on each of the six sides of the hexagon. Thus the magnetic field alternates on each side of the hexagon. The wiggy-chain undulator magnetic field is numerical evaluated.

Key words: Free electron laser; Electromagnetic undulatory