Analysis and measurements of permanent magnet ´bifilar´ helical wigglers

Analysis and measurements of the permanent magnet ´bifilar´ helical wiggler, composed of a cylindrical array of staggered bar magnets are presented. The discreteness of the magnets is taken into account, thus enabling a calculation of the field strengths of the fundamental and higher spatial harmonics. Calculations show that the performance of this wiggler is expected to be comparable or to better than that of a planar wiggler similar parameters. In addition, samarium-cobalt-iron hybrids in which soft iron tubes were used to enhance and/or taper the wiggler field amplitude were studied experimentally and analytically.<>