1991, 13(3): 271-277.
Abstract:
In general, in free electron lasers there two kinds of stimulated radiations. FEL radition and cyclotron ralition. It is shown theoretically, if the initial transverse velocity of electron is large and the selected parameters for FEL are not suitable, the cyclotron radiation will be dorninant, especially when the energy of electron beam is low. But the cyclotron radiation does not have double Doppler frequency up-shift effect, is frequency is limited by axial magnetic field, when the energy of electron beam is low. But the cyclotron radiation does not have double Doppler frequency up-shift effect, is frequency is limited by axial
magnetic field, when the energy of electron beam is high, the cyclotron radiation frequency will be much lower than FEL radiation frequency. Therefore, in FEL experiments how to distinguish these two kinds of radiations and to suppress the cyclotron radiation are very important.