ON A MODIFIED BERNOULLI CURRENT UNDULATOR

摘要

A current undulator for free electron lasers was presented. The Bernoulli structure produces magnetic fields which are spatially periodic. The structure has the shape of modified Bernoulli wire stacks. The current has alternating directions. The magnetic field components for each wire present a 90 degree symmetry. The modified Bernoulli undulator transverse cross-section was given by the relations: x = 2·α~2cos(2θ)cos(θ); y = 2·α~2cos(2θ)sin(θ); z = const., a is a parameter. The Biot-Savart law in the polar coordinates was evaluated. The magnetic field was mainly logitudinal and easily adjusted with the current. The versatility of this structure was designed for two beams longitudinal undulator or wiggler with transverse momenta.