Contribution to the theory of parametric generation of cyclotron radiation

A linear theory of the cyclotron parametric instability in systems which are classical analogues of quantum lasers without inversion is developed. The cyclotron interaction of different types of modulated electron beams with a bichromatic field, produced by waves propagating at an angle with respect to a constant magnetic field, is investigated. It is shown that simultaneous amplification of two parametrically coupled modes with different frequencies and positive energy is possible in this system with modulation of the active and reactive components of the susceptibility of an electronic ensemble. The results obtained are important from the standpoint of the general theory of radiation processes in electron beams and plasma and for the advancement of microwave electronics.