Analysis of Radiation Emitted by Variable Polarizing Undulators

In this research, the planer and variable polarizing undulators are investigated and compared. Regarding field equations in to the undulators, independent relativistic electron approximation and Lorentz's force, the trajectories of electrons in undulators are calculated. Using calculated electrons' acceleration, theory of accelerated charged particle radiation and Lienard-Wiechert equation, the power of free electron laser are investigated. Complexity of the obtained equations and their analytical difficulty caused numerical investigation of the results. The results are represented by two and three dimensional diagrams. The comparison of output power from free electron laser with variable polarizing undulator and with planer undulator show that output power of helical undulators are more than linear undulators. For helical undulators with zero phase difference, the maximum output power is at the points where summation of square of undulator parameters is equal to a constant. The role of the phase difference in the helical undulator has been investigated. The results showed that with π/4 and π/2 phase differences, output power of free electron laser at equal undulator parameters are maximum. Comparison of these two state showed that output power with phase difference of ( π)/2 is more than π/4. The harmonics of planer and variable polarizing system are evaluated and compared.