Design of a Permanent Magnet Wiggler for a THz Free Electron Laser

A THz free electron laser is being built in Ariel University. Upon completion it is intended to become a user facility. The free electron laser is designed to emit radiation between 1 and 5 THz. It is planned to operate in the super radiance regime. The anticipated output of the free electron laser is in excess of 150 kW instantaneous power. An essential part of every free electron laser is a device generating a periodic magnetic field denoting the wiggler. Here we describe a design of a classical Halbach type permanent magnetic wiggler for the THz free electron laser. The main novelty in this paper is the choice of wiggler parameters suitable for operation in the THz frequency range. Considerations such as radiation wave length, wiggler gain and electron optics are taken into account.