Design of a fast tunable polarized FEL based on a microwave undulator

A high-power microwave undulator with tunable polarization is analyzed. The construction of the undulator cavity is designed. When TE
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microwave with a peak power of 800MW at 9.7 GHz fed into the cavity, the equivalent magnetic field of 0.3T are got. The equivalent period of the forward and backward microwave undulator are derived. The basic theory and dispersion relations of the FEL are studied. With 700 kV and 7 kA electron beam, the expected radiation frequency is 120.5 GHz. The brief introduction and primary setup of the fast tunable polarized FEL with the microwave undulator are described.