The property of universality for wigglers and invariance of electromagnetic radiation

This paper deals with the electromagnetic radiation generated in any planar pure permanent magnet wiggler. The following mental modification of the wiggler magnetic system is theoretically investigated: the easy axis of all magnetic blocks, which compose the wiggler, are rotated by the special low, while the wiggler geometry remains intact. This evidently causes the wiggler magnetic field to change in shape and amplitude. However it can be proved that the total power of wiggler radiation along with the wavelengths of radiated harmonics is invariant under this transformation. The change of magnetic field involves a variation in intensities of the radiation harmonics.